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Conte, Stan

Mayo Clinic

University of Utah

Citations 19

Poster 44: Outcomes of Revision Elbow Medial Ulnar Collateral Ligament Reconstruction in Professional Baseball Players: an Analysis of 191 Pitchers from 2010 to 2023
Chalmers, Peter N., Conte, Stan, Griffith, Timothy B. , Ma, Kevin , D’Angelo, John, Herbert, Liz, Simon, Karissa N. , Erickson, Brandon J. , Chalmers, Peter N. , Griffith, Timothy Bryan , D’Angelo, John, Herbert, Liz, Camp, Christopher L.

Orthopaedic Journal of Sports Medicine | September 26, 2025 | Volume: 13 | Issue: 9_suppl3 | Pages: No page available

10.1177/2325967125s00155 Get It

Objectives: The number of medial ulnar collateral ligament (MUCL) reconstructions are increasing. The epidemiology surrounding revision MUCL reconstructions in professional baseball players has not been well defined. The purpose of this study was to report the epidemiology of revision MUCL reconstruction in professional baseball players. The authors hypothesized that the number of revision MUCL reconstructions would increase over time and that the return to sport rate at the same level of play would be less than 70%. Methods: All professional baseball pitchers who underwent revision MUCL reconstruction between 2010-2023 were identified using the MLB Health and Injury Tracking System (HITS). Rate of return and time to return to play (RTP) and return to same level of play (RTSL) was recorded and analyzed for pitchers with a minimum follow up of 2 years. Surgical variables including technique and graft choice were also recorded. Results: Overall, 191 pitchers (avg age 26.0 years), underwent revision MUCL reconstruction. The average time between primary and revision surgery was 1,381 days (45 months). 130 (68%) of these players were MLB pitchers and the other 61 (32%) were MiLB pitchers. 59% of pitchers were able to RTSL at an average of 604 ± 250 days after surgery. 2023 was the year with most revision MUCL reconstructions (n = 27) and the fewest reconstructions were performed in 2010 and 2011 (n = 4). Monthly distribution demonstrates the highest surgery months to be May (17%), June (20%), and July (17%). Hamstring tendon autograft was found to be the most commonly used graft source (n = 90, 47%), compared to palmaris longus autograft (n = 67, 35%). No significant differences were found in the types of grafts used over time ( P = .238 for palmaris and P = .133 for hamstring). In terms of tunnel configuration, both the Modified Jobe and Docking techniques were used in equal occurrence (n = 70, 37%) Conclusions: Following revision MUCL reconstruction, only 72% of professional baseball pitchers were able to return to play at any level at an average of 556 days (18 months), and only 59% were able to return to the same level of play at an average of 604 days (20 months). The average time between primary and revision MUCL reconstruction was 45 months (3.75 years). Pitchers should be counseled on the relatively low RTSL rate and the prolonged time to RTSL.
Epidemiology of Elbow Medial Ulnar Collateral Ligament Surgeries in Major and Minor League Baseball Pitchers: A Descriptive Study of 2281 Cases
Meta, Fabien , Meister, Keith, Griffith, Timothy B. , Conte, Stan, Chalmers, Peter N., Mavrommatis, Sophia , Hebert, Elizabeth, Clark, Sean C. , Griffith, Timothy Bryan , Chalmers, Peter N. , Hebert, Elizabeth, Camp, Christopher L.

Orthopaedic Journal of Sports Medicine | July 7, 2025 | Volume: 13 | Issue: 7 | Pages: No page available

10.1177/23259671251352199 Get It

Background: Injuries of the medial ulnar collateral ligament (MUCL) among baseball pitchers are increasing. Surgical treatment is evolving to optimize outcomes. Purpose/Hypothesis: This study’s purpose was to highlight trends in MUCL repair and reconstruction in professional pitchers, describe outcomes such as return to any level of play (RTP), and identify factors impacting these outcomes. It was hypothesized that primary and revision MUCL surgery is increasing, with revision surgery requiring greater RTP time. Study Design: Case series; Level of evidence, 4. Methods: The Major League Baseball (MLB) Health and Injury Tracking System database was used to procure data during the study period (2010-2023). All professional pitchers who underwent MUCL surgery during this period were included. RTP was defined as a pitcher returning to at least 1 professional game after index surgery. Return to the same level of play (RTSL) was defined as return to at least 1 game in the same league of play as before surgery. Because of the coronavirus pandemic, the year 2020 was considered an outlier and omitted from time-trend analysis. Results: A total of 2281 pitchers who underwent MUCL surgery during the study period were included for analysis. The number of MUCL surgeries for pitchers increased yearly ( R 2 = 0.821; P < .001), as did the number of reconstructions with internal brace augmentation ( R 2 = 0.896; P < .001). The RTP rate for MLB pitchers was significantly higher than the RTSL rate (93% vs 71%; P < .001). This difference was not observed in Minor League Baseball (MiLB) pitchers (RTP 76% vs RTSL 74%; P = .142). RTP rates after revision surgery were lower than those after primary surgery (71% vs 80%; P = .020). The mean time to RTP was shorter (470 ± 135 days) than the mean time to RTSL (499 ± 153 days; P < .001). Conclusion: The incidence of MUCL surgery and revision surgery is increasing among professional pitchers. Overall, 79% of pitchers returned to any level of play at a mean of 470 days, while 74% returned to the same level of play at a mean of 499 days, but this varied based on level of play. This study will guide athlete expectations and surgeon decision-making.
Abdominal Oblique and Rectus Muscle Injuries in Major and Minor League Baseball Players: An Updated Epidemiological Review
Tenner, Zachary M. , Lamba, Abhinav , Griffith, Timothy B. , Conte, Stan, Camp, Christopher L. , Lamba, Abhinav , Griffith, Timothy Bryan

Orthopaedic Journal of Sports Medicine | November 15, 2024 | Volume: 12 | Issue: 11 | Pages: No page available

10.1177/23259671241293454 Get It

Background: Abdominal musculature injuries comprise the third most prevalent time-loss injury across professional baseball. Despite increased awareness and prevention attempts in the recent decade, the trends of these abdominal injury numbers in Major League Baseball (MLB) are not fully understood. Purposes: To update the trends in oblique and intercostal injuries, analyze the impact of these injuries based on time out of play, and identify factors that correlate with increased injury severity to help with recovery time prognostication for the sports medicine community. Study Design: Descriptive epidemiology study. Methods: Using the MLB Health and Injury Tracking System, the authors identified all abdominal and core musculature injuries that resulted in time out of play in MLB and Minor League Baseball (MiLB) between the 2011 and 2021 seasons. These were filtered for injuries that resulted in ≥1 days missed (DM) during spring training, the regular season, and postseason. A Student t test was utilized to assess for significant differences for all normally distributed values. Regression analysis was utilized for determining change over time. For all statistical comparisons, the threshold for alpha was set to P < .05. Results: During the study period between 2011 and 2021, there were 4560 total abdominal injuries among 3401 athletes. When filtered for in-season, time-loss injuries defined as spring training, regular season, and postseason, there were 2890 injuries. Of these, 1928 were oblique injuries, 453 were intercostal injuries, and 115 were rectus injuries. The number of oblique injuries each season increased for all of baseball ( P < .001), as well as for MLB ( P = .009) and MiLB ( P = .012) individually. Of the 1928 oblique injuries, 498 (26%) oblique injuries occurred at the MLB level and 1430 (74%) occurred at the MiLB level. Batting and pitching-related injuries comprised 860 (45%) and 729 (38%) oblique injuries, with a total of 18,455 DM and 20,891 DM, respectively. This corresponded to a mean of 22 DM for batting injuries and 29 DM for pitching injuries (mean difference, 7.2; 95% CI, 5.27-9.13; P < .001). Conclusion: This decade-long study on professional baseball revealed a significant increase in abdominal oblique injuries across MLB and MiLB, with the largest number of injuries observed in the 2021 season. Meanwhile, there was a significant decrease in intercostal injuries across professional baseball during these years. Such injuries continue to pose challenges, leading to substantial DM per injury and affecting players from various positions.
Shoulder Injuries in Professional Baseball Batters: Analysis of 3,414 Injuries Over an 8‐Year Period
Marigi, Erick M. , Conte, Stan, Reinholz, Anna K., Steubs, John A. , Krych, Aaron J. , Camp, Christopher L. , Camp, Christopher L. , Krych, Aaron J , Marigi, Erick , Knudsen, Michael L.

Arthroscopy, Sports Medicine, and Rehabilitation | May 21, 2022 | Volume: 4 | Issue: 3 | Pages: No page available

10.1016/j.asmr.2022.03.012 Get It

Purpose To characterize the shoulder injuries experienced by baseball batters and position players (nonpitchers); to quantify the outcomes of these injuries with respect to time out of play, recurrence, and surgery rates; and to identify any injury patterns that are associated with worse outcomes. Methods Between 2011 and 2017, all Major League Baseball (MLB) and Minor League Baseball (MiLB) players who sustained shoulder injuries were identified using the MLB Health and Injury Tracking System (HITS). Injuries were included if they were sustained during baseball activity, resulted in at least 1 day missed (DM), and occurred in position players (nonpitchers). Results Over the study period, a total of 3,414 shoulder injuries occurred in batters, resulting in a sum of 68,808 DM and a mean of 22 DM per injury. Most injuries were a result of acute trauma (n = 2125; 62.2%) with throwing as the predominant activity (n = 1292; 38%). Rotator cuff strain/tears was the most common diagnosis (n = 790; 23.1%), and SLAP tears had the highest season‐ending rate (35.3%) and need for surgery (45.1%). There was a lower frequency of surgery (6.2% vs 9.2%; P = .002) and reinjury (2.03% vs 3.62%; P = .007) in the throwing shoulder vs the nonthrowing shoulder. There was an increased frequency of surgery for the front versus the back batting shoulder (8.2% vs 6.2%; P = .031) with similar DM (20.7 vs 22.2; P = .333) and return to play rates (94.0% vs 92.2%; P = .135). Conclusions During the 7‐season study period, there were a total of 3,414 shoulder injuries that resulted in nearly 70,000 days of out of play in professional baseball position players/batters (nonpitchers). Although pitchers were intentionally excluded from the analysis, throwing was still the most common mechanism of injury, and rotator cuff injuries were the most common injury. Labral tears were the most likely injury to be season ending and require surgery. Clinical Relevance This study is meant to help determine characteristics of shoulder injuries that occur in non‐pitchers by focusing on professional baseball batters and position players. This information could be helpful to sports medicine practitioners and shoulder specialists to better prognosticate injury recovery.
Correlation of Rehabilitation and Throwing Program Milestones With Outcomes After Ulnar Collateral Ligament Reconstruction: An Analysis of 717 Professional Baseball Pitchers
Griffith, Timothy B. , Conte, Stan, Poulis, George C., Diamond, Adam , D’Angelo, John , Griffith, Timothy Bryan , Camp, Christopher L.

The American Journal of Sports Medicine | May 9, 2022 | Volume: 50 | Issue: 7 | Pages: 1990-1996

10.1177/03635465221093995 Get It

Background: There remains room for improvement in surgical outcomes after medial ulnar collateral ligament reconstruction (MUCLR) in professional pitchers. The role and influence of postoperative rehabilitation on the outcomes of MUCLR are unknown. There is a paucity of clinical data in the current literature comparing the success of various postsurgical rehabilitation protocols after MUCLR. Purpose: To summarize the current rehabilitation process for professional pitchers recovering from MUCLR, evaluates what player and surgical factors correlate with outcomes, and determines whether rehabilitation timing and milestones correlate with successful outcomes. Study Design: Case series; Level of evidence, 4. Methods: 717 professional baseball pitchers who underwent MUCLR between 2010 and 2016 were identified and included in the analysis. Player characteristics evaluated included age at the time of surgery, throwing side dominance, primary pitching role (starter vs reliever), and level of play (MLB, AAA, AA, A). Surgical factors studied included date of surgery, graft type (palmaris longus autograft vs gracilis autograft), and surgical technique (figure of 8 vs docking vs other). The rehabilitation and throwing progression details were as follows: initiation date; first throw date; dates to start throwing from various distances; longest distance thrown; first flat ground throw date; first mound throw date; and first live batting practice (BP) date. The primary outcomes of interest were the ability to return to play at any level (RTP), the ability to return to the same level (RSL), and the time to RTP/RSL. Results: On average, pitchers threw a baseball for the first time 4.9 months after surgery, with a broad range (2.8-14.9 months). For the 675 (94%) pitchers who were able to progress to mound throwing, the first throws off a mound occurred at a mean of 9.4 months after surgery. Before progressing to the mound, the mean longest long-toss distance reached was 137.5 feet, with a broad range (105-300 feet). A high variation in the time to RTP (7.6-53.9 months) and RSL (8.6-60.7 months) was noted. A total of 599 (84%) pitchers were able to RTP at a mean time of 14.9 ± 4.9 months after surgery (range, 7.6-53.9 months). Also, 528 (74%) pitchers were able to RSL after MUCLR at a mean of 17.4 ± 7 months (range, 8.6-60.7 months) postoperatively. Age was the most significant predictor of RTP (hazard ratio [HR], 1.03 [95% CI, 1.01-1.05]; P = .01) and RSL (HR, 0.96 [95% CI, 0.93-0.99]; P < .01). For every 1-year increase in age, there was a 3% increase in the chance of RTP. Conversely, for every 1-year decrease in age, there was a 4% increase in the chance of RSL. MLB players were more likely to RTP (HR, 1.39 [95% CI, 1.18-1.63]; P < .01) but not necessarily to RSL (HR, 0.90 [95% CI, 0.75-1.08]; P = .24). The time from surgery to any of the rehabilitation milestones of interest (first throw, first flat ground pitching, first mound throwing, and first live BP) did not correlate with RTP or RSL (all, P >.05). The same was true for the greatest long-toss distance thrown before transitioning to the mound. Conclusion: Significant variability in the postoperative rehabilitation protocols after MUCLR was observed in 717 professional baseball pitchers. The timing of achievement of throwing progression and rehabilitation milestones postoperatively varied widely but did not correlate with outcomes. Player characteristics—except for player age and professional pitching level—did not correlate with RTP and RSL outcomes. Older pitchers and MLB pitchers were more likely to RTP, but younger players were more likely to RSL. Surgical factors did not correlate with rehabilitation outcomes.
Are Baseball Statistics an Appropriate Tool for Assessing Return to Play in Injured Pitchers? Analysis of Statistical Variability in Healthy Players
Pareek, Ayoosh , Parkes, Chad W. , Leontovich, Alexey A. , Krych, Aaron J. , Conte, Stan, Steubs, John A. , Wulf, Corey A., Krych, Aaron J , Camp, Christopher L.

Orthopaedic Journal of Sports Medicine | November 18, 2021 | Volume: 9 | Issue: 11 | Pages: No page available

10.1177/23259671211050933 Get It

Background: Basic pitcher statistics have been used to assess performance in pitchers after injury or surgery without being validated. Even among healthy pitchers, the normal variability of these parameters has not yet been established. Purpose: To determine (1) the normal variability of basic and advanced pitcher statistics in healthy professional baseball pitchers and (2) the minimum pitches needed to predict these parameters. Study Design: Cross-sectional study; Level of evidence, 3. Methods: Publicly available data from the MLB Statcast and PITCHf/x databases were used to analyze MLB pitchers during the 2015 and 2016 seasons who recorded a minimum of 100 innings without injury. Basic and advanced baseball pitcher statistics were analyzed. The variability of each parameter was assessed by computing the coefficient of variation (CV) between individual pitchers and across all pitchers. A CV <10 was indicative of a relatively constant parameter, and parameters with a CV >10 were generally considered inconsistent and unreliable. The minimum number of pitches needed to be followed for each variable was also analyzed. Results: A total of 118 pitchers, 55 baseball-specific statistical metrics (38 basic and 17 advanced), and 7.5 million pitches were included and analyzed. Of the 38 basic pitcher statistics, only fastball velocity demonstrated a CV <10 (CV = 1.5), while 6 of 17 (35%) advanced metrics demonstrated acceptable consistency (CV <10). Release position from plate and velocity from the plate were the 2 most consistent advanced parameters. When separated by pitch type, these 2 parameters were the most constant (lowest CV) across every pitch type. Conclusion: We recommend against utilizing nonvalidated statistical measures to assess performance after injury, as they demonstrated unacceptably high variability even among healthy, noninjured professional baseball pitchers. It is our hope that this study will serve as the foundation for the identification and implementation of validated pitcher-dependent statistical measures that can be used to assess return-to-play performance after injury in the future.
Prevalence of Medial Ulnar Collateral Ligament Surgery in 6135 Current Professional Baseball Players: A 2018 Update
Leland, Devin P. , Conte, Stan, Flynn, Nancy , Conte, Nicholas F., Crenshaw, Ken, Wilk, Kevin E., Conte, Nicholas, Camp, Christopher L.

Orthopaedic Journal of Sports Medicine | September 25, 2019 | Volume: 7 | Issue: 9 | Pages: No page available

10.1177/2325967119871442 Get It

Background: As the incidence of ulnar collateral ligament (UCL) surgery continues to rise rapidly, an update on the current prevalence and demographics in professional baseball players is warranted. Hypothesis: The prevalence of UCL reconstruction in Major League Baseball (MLB) and Minor League Baseball (MiLB) players will be higher than that previously reported, and the increase in prevalence will be most notable in MiLB pitchers. Study Design: Cross-sectional study; Level of evidence, 3. Methods: During the 2018 baseball season, an online questionnaire regarding a history of UCL surgery was distributed to the certified athletic trainers of all 30 MLB organizations. These trainers then administered the survey to all players within their organizations, including MLB, MiLB (AAA, AA, High A, Low A, High Rookie, Low Rookie), and Dominican Summer League (DSL) players. Demographics were compared between MLB, MiLB, and DSL players. Results of this 2018 survey were compared with previously published data from the 2012 season to assess the change over time. Results: There were 6135 professional baseball players who completed the survey (66% response rate). The prevalence of UCL reconstruction in all MLB and MiLB players was 13% (637/4928), while the prevalence in DSL players was 2% (20/1207) ( P < .001). The prevalence in all MLB and MiLB players (13%) and pitchers (20%) both increased significantly from 2012 ( P < .001). MLB pitchers reported a higher prevalence of UCL reconstruction than did MiLB pitchers (26% vs 19%, respectively; P < .001). In 2018, the prevalence of UCL reconstruction has increased significantly in MiLB pitchers (19% vs 15%, respectively; P < .001) and pitchers aged 21 to 30 years (22% vs 17%, respectively; P < .001) compared with 2012. Additionally, United States–born pitchers were more likely to have undergone UCL reconstruction compared with Latin America–born pitchers (23% vs 13%, respectively; P < .001). Conclusion: The prevalence of UCL reconstruction has increased significantly in professional baseball players over the past 6 years from 10% to 13%. Ultimately, the prevalence of UCL reconstruction has increased most significantly since 2012 in MiLB pitchers, pitchers aged 21 to 30 years, and pitchers born in the United States.
Variability in Baseball Throwing Metrics During a Structured Long-Toss Program: Does One Size Fit All or Should Programs Be Individualized?
Leafblad, Nels D. , Conte, Stan, Fealy, Stephen A., D’Angelo, John , Larson, Dirk R. , Fleisig, Glenn S. , Dines, Joshua S. , Camp, Christopher L.

Sports Health: A Multidisciplinary Approach | September 3, 2019 | Volume: 11 | Issue: 6 | Pages: 535-542

10.1177/1941738119869945 Get It

Background: The variability of throwing metrics, particularly elbow torque and ball velocity, during structured long-toss programs is unknown. Hypotheses: (1) Elbow torque and ball velocity would increase as throwers progressed through a structured long-toss program and (2) intrathrower reliability would be high while interthrower reliability would be variable. Study Design: Descriptive laboratory study. Level of Evidence: Level 3. Methods: Sixty healthy high school and collegiate pitchers participated in a structured long-toss program while wearing a validated inertial measurement unit, which measured arm slot, arm velocity, shoulder rotation, and elbow varus torque. Ball velocity was assessed by radar gun. These metrics were compared within and between all pitchers at 90, 120, 150, and 180 ft and maximum effort mound pitching. Intra- and interthrower reliabilities were calculated for each metric at every stage of the program. Results: Ball velocity significantly changed at each progressive throwing distance, but elbow torque did not. Pitching from the mound did not place more torque on the elbow than long-toss throwing from 120 ft and beyond. Intrathrower reliability was excellent (intraclass correlation coefficient >0.75) throughout the progressive long-toss program, especially on the mound. Ninety-one percent of throwers had acceptable interthrower reliability (coefficient of variation <5%) for ball velocity, whereas only 79% of throwers had acceptable interthrower reliability for elbow torque. Conclusion: Based on trends in elbow torque, it may be practical to incorporate pitching from the mound earlier in the program (once a player is comfortable throwing from 120 ft). Ball velocity and elbow torque do not necessarily correlate with one another, so a degree of caution should be exercised when using radar guns to estimate elbow torque. Given the variability in elbow torque between throwers, some athletes would likely benefit from an individualized throwing program. Clinical Relevance: Increased ball velocity does not necessarily equate to increased elbow torque in long-toss. Some individuals would likely benefit from individualized long-toss programs for rehabilitation.
Revision Ulnar Collateral Ligament Reconstruction in Professional Baseball: Current Trends, Surgical Techniques, and Outcomes
Desai, Vishal S. , Conte, Stan, Ciccotti, Michael C., Altchek, David W. , D’Angelo, John , Griffith, Timothy B. , Desai, Vishal , Camp, Christopher L. , Ahmad, Christopher S. , Dines, Joshua S. , Griffith, Timothy Bryan

Orthopaedic Journal of Sports Medicine | August 14, 2019 | Volume: 7 | Issue: 8 | Pages: No page available

10.1177/2325967119864104 Get It

Background: Ulnar collateral ligament (UCL) reconstruction of the elbow is commonly performed on professional baseball pitchers. Recent reports have suggested that revision rates are on the rise and may be higher than previously thought. Purpose: To provide a comprehensive report on current trends, surgical techniques, and outcomes of revision UCL reconstructions performed on professional baseball pitchers between 2010 and 2016. Study Design: Case series; Level of evidence, 4. Methods: The Major League Baseball Health and Injury Tracking System (HITS) was used to compile records of all revision UCL reconstructions performed on professional baseball pitchers between 2010 and 2016. Player data and outcomes were obtained from HITS, and surgical details were obtained from operative reports. Descriptive statistical analysis was performed on epidemiologic data. Outcomes (return to play [RTP] rates, RTP times, subsequent injuries, and subsequent surgeries) were compared across the most common surgical techniques (docking vs modified Jobe) and graft sources (palmaris longus autograft vs hamstring autograft). Results: A total of 69 professional baseball pitchers underwent revision UCL reconstruction from 2010 to 2016 at an average of 1424 days (47 months) after their primary surgery. A trend was seen toward increasing numbers of revision surgeries over time ( R 2 = 0.441; P = .104). The most commonly used tunnel configuration was the modified Jobe technique (n = 41; 59.4%), and the most commonly used graft was hamstring autograft (n = 34; 49.3%). A majority (76.6%) of pitchers achieved RTP, and 55.3% were able to return to the same level of play. Mean time to RTP was 436 days (14.5 months) for players with a palmaris longus autograft versus 540 days (18 months) for those with a hamstring autograft ( P = .108). Further, the mean time to RTP was 423 days (14 months) for the docking technique versus 519 days (17 months) for the modified Jobe technique ( P = .296). Similar rates of subsequent injuries and surgeries were noted between the 2 revision techniques and 2 most commonly used graft constructs. Conclusion: Revision UCL reconstruction showed relatively high RTP rates (77%), but only 55% of players returned to their same level of play. Mean time to RTP was shorter than that found in other, smaller investigations. Although general trends were seen toward decreased time to RTP for the docking technique and palmaris longus autograft, these differences did not reach statistical significance.
Hamstring Injury Trends in Major and Minor League Baseball: Epidemiological Findings From the Major League Baseball Health and Injury Tracking System
Okoroha, Kelechi R. , Conte, Stan, Lizzio, Vincent A. , Li, Bernard, Makhni, Eric Chugh , Camp, Christopher L. , Ahmad, Christopher S.

Orthopaedic Journal of Sports Medicine | July 30, 2019 | Volume: 7 | Issue: 7 | Pages: No page available

10.1177/2325967119861064 Get It

Background: Hamstring strains are the most common injury for professional baseball players and can result in significant time on the disabled list. To date, no study has reported the current trends in hamstring strains in professional baseball. Hypothesis: Professional baseball players would have an increased incidence of hamstring strains from 2011 through 2016. Study Design: Descriptive epidemiology study. Methods: Injury data were prospectively collected from 2011 through 2016 for every Major League Baseball (MLB) and Minor League Baseball (MiLB) team and was recorded in the MLB Health and Injury Tracking System. Data collected for this study included date of injury, activity during injury, time lost, primary injury or reinjury status, and imaging findings as well as player demographic information related to level of play, age, and position for all hamstring injury events. Injury rates were reported as hamstring injuries per number of games. Results: From 2011 to 2016, there were 2633 hamstring strains in professional baseball players. The rate of hamstring strains increased in MLB from a low of 1 injury every 39 games in 2011 to a high of 1 injury every 30 games in 2016. In MiLB, there were 2192 hamstring strains, with 1 injury every 35 games in 2011 compared with 1 injury every 30 games in 2016. The majority of injuries occurred in the infielder positions (37.5%) and resulted from base running (>50%), most commonly from home to first base. The most common hamstring injury was a grade 2 injury to the distal biceps femoris. The mean time missed after a hamstring injury was 14.5 days. Grade 3 and grade 2 hamstring strains resulted in significantly more days missed compared with grade 1 injuries ( P = .005 and P = .002, respectively). The rate of recurrent hamstring injuries was 16.3% for MLB and 14.2% for MiLB. Recurrent hamstring injuries resulted in more time lost than primary injuries (mean, 16.4 vs 14.5 days, respectively; P = .02). A total of 42 injuries were treated with platelet-rich plasma, and 19 were treated with surgery. The number of injuries treated with platelet-rich plasma increased in successive years. Conclusion: The rate of hamstring strains in professional baseball players has increased over the past 6 years and has resulted in a significant loss of playing time. Study results indicated that these injuries are affected by injury characteristics, position played, running to first base, seasonal timing, and history of hamstring injuries.