Refers to a now-common surgery performed first on Tommy John in in which a ligament from another part of the body is attached to the elbow of the patient, replacing a damaged ligament that prohibited forceful throwing from that arm. The new ligament attaches to the elbow and often enables the patient to throw with former or greater force.
Tommy John surgery used to be questionable in its early days, but now is an accepted procedure that results in its patients throwing as hard or harder than before the surgery. The procedure has become fairly common in recent years as more pitchers (the primary subjects for this surgery) break down due to excessive use of the arm. A high majority of these pitchers return to playing within about a year after the surgery, through careful rehabilitation of their throwing arm. Some of these pitchers go on to perform more effectively after the surgery.