Background We sought to determine whether professional baseball positional players who underwent medial ulnar collateral ligament (MUCL) reconstruction demonstrate decreases in performance on return to competition compared with preoperative performance metrics and their control-matched peers. Methods Data for 35 Major League Baseball positional players who underwent MUCL reconstruction during 31 seasons were obtained. Twenty-six players met inclusion criteria. Individual statistics for the 2 seasons immediately before injury and the 2 seasons after injury included wins above replacement (WAR), on-base plus slugging (OPS), and isolated power (ISO). Twenty-six controls matched by player position, age, plate appearances, and performance statistics were identified. Results Of the 35 athletes who underwent surgery, 7 did not return to their preinjury level of competition (return to play rate of 80%). In comparing preinjury with postinjury statistics, players exhibited a significant decrease in plate appearances, at-bats, and WAR 2 seasons after injury but did not demonstrate declines in WAR 1 season after injury. Compared with matched controls, athletes who underwent MUCL reconstruction did not demonstrate significant decline in statistical performance, including OPS, WAR, and ISO, after return to play from surgery. Of all positional players, catchers undergoing surgery demonstrated lowest rates of return to play (56%) along with statistically significant decreases in home run rate, runs batted in, and ISO. Conclusion Major League Baseball positional players undergoing MUCL reconstruction can reasonably expect to return to their preinjury level of competition and performance after surgery compared with their peers. Positional players return to play at a rate comparable to that of pitchers; catchers may experience more difficultly in returning to preinjury levels of play.