In recent seasons, a small elbow ligament has had an outsized impact on the national pastime.
Over a third of Major League Baseball (MLB) pitchers have undergone ulnar collateral ligament (UCL) reconstruction surgeries – known popularly as Tommy John surgery – according to tracking data by baseball data researcher Jon Roegele. The widespread impact of the record number of surgeries that require a long recovery window has sent players, physicians and the MLB looking for answers.