Background: Medial ulnar collateral ligament reconstruction surgery (UCLR) is a common surgical procedure performed on elite level baseball players. Physical signs and symptoms of ulnar collateral ligament (UCL) injuries requiring UCLR along with treatment have been clearly defined, however, an exact etiology of UCL injuries and methods of preventing UCLR surgery remain unclear. Objective: Systematically review and qualitatively provide an in-depth summary of recent literature about the relationships between changes in advanced pitching metrics for potential warning signs of UCL injury prior to requiring UCLR. Methods: We searched two electronic databases (PubMed, Scopus) from inception to October 2021 using a keyword search. Data extracted included author and year of publication, study design, sample size, study location, and primary outcome variables. Articles that met inclusion criteria were then evaluated using a modified Downs and Black criteria. Results: The key word search returned 51 articles of which a total of seven articles were included in the review. For the papers that met the inclusion criteria, four noted changes to velocity as potential an indicator for UCLR surgery, two identified lateralization of arm angles as an indicator of UCLR surgery, and one reported change to spin rates of specific pitches as an indicator for UCLR surgery. Conclusions: The results of this review show that changes in certain advanced pitching metrics such as spin rate, velocity, and lateralization of arm angles could be potential indicators of UCL damage. Further evaluation is needed to continue to improve our understanding of how these trends could be used as predictors of UCLR.

The purpose of this thesis is to determine what effects draft order, monetary earnings, and Tommy John Surgery (TJS) have on the perceived value of a pitcher in Major League Baseball (MLB). For the context of this thesis, value will be defined as a player's ability to contribute to their team's wins in a positive manner. TJS has become synonymous with MLB and baseball as a sport, and many are either skeptical of its effects or over-assuming of its benefits. The three aforementioned areas of concerns were used to structure the thesis, as each dependent outcome is analyzed in a chapter of its own. Multiple articles and studies pertaining to the effects draft order, financial earnings, and TJS may have on pitcher value were compiled and analyzed. Looking at studies between pitchers who underwent TJS prior to being drafted, their order by which they are picked by a team is not as affected as assumed, but the pitcher is more likely to return to the disabled/injured list during their career in MLB. A lens of economic value saw that pitchers who were paid more added to their teams' respective wins. However, the financial loss caused by a pitcher missing time to recover from TJS could outweigh the cost of wins. From a purely Tommy-John standpoint, there are significant changes both beneficial and detrimental to a pitcher's overall statistics. Further research and personal knowledge should be explored prior to receiving TJS as a pitcher. Overall, the factor of TJS seems to have a slightly negative influence on the other two factors and an overall stronger influence than draft order or monetary earnings.