Early last week, Mets outfielder Juan Lagares was placed on the disabled list with a partially torn ligament in his thumb. Although not explicitly stated by the team, the ligament likely torn is the ulnar collateral ligament (UCL). Lagares initially injured his thumb on June 4 after making a spectacular diving catch (video below); after unsuccessful attempts to play through the pain, the team finally decided to place him on the DL.
What is the UCL?
A ligament is connective tissue that connects two bones together; in this case the UCL is on the inner side of the thumb and connects the metacarpal (bone in the palm) to the phalanx (bone above the knuckle) . There are several UCLs in the body, most notably in the elbow joint, which, if torn, invariably leads to Tommy John surgery. The thumb UCL acts as the main stabilizer during gripping, and ligaments in general contribute to stability of the joint. Thus, a torn UCL impairs the player's ability to grip the ball and bat while increasing the chances of a dislocated thumb. This injury is commonly known as "Skier's thumb" or "Gamekeeper's thumb."
Jets fan have seen this injury before, as Ryan Fitzpatrick injured the same ligament last season after diving in a game with the Bills.
What is the recovery process like?
Because the UCL is partially torn, surgery is not necessarily required. With the nonsurgical route, the thumb is splinted for about three weeks before beginning rehab. As soon as the splint is removed, the medical staff will work with Lagares towards regaining full range of motion and grip strength before starting any sport-specific activity.
Grip strength is crucial for a baseball player as it allows him to transfer the power he has created with his body to the bat as the bat makes contact with the ball. Poor grip strength would result in the player's not having full control of the bat throughout the swing. In addition, the same muscles are used to catch the baseball.
It should take between 6-8 weeks for the ligament to heal completely and for Lagares to complete a rehab stint in the minors. Assuming no setbacks, we could see Lagares return to the team in the middle of August.