He may have a torn medial collateral ligament (MCL). This ligament is made up of three separate bundles of fibers that blend into one another. Along with the ligament complex on the outside of the elbow, these soft tissues form the capsule around the elbow joint. The capsule envelopes the elbow, holds the bones together, and provides stability during overhead activities.
In the normal elbow, a significant amount of force can be applied to the elbow during the overhead throwing motion. The ligaments of the elbow combined with the forearm muscles seem to dissipate the energy force created by this motion.
But chronic overuse of the throwing motion can cause microtears in the ligaments that don't heal. Over time, with enough use and trauma, a partial tear or complete rupture of the ligament can occur.
When that happens, the athlete may not feel pain until as much as 80 per cent of the throwing motion is complete. In some cases, pain may not occur until after throwing. It may require a medical evaluation to know for sure. An orthopedic surgeon or sports physician can assess the arm and elbow to find out what's going on.
Early detection of problems and treatment right away can help prevent worsening of the condition. Sometimes rest, activity modification, and a specific rehab program can heal the damage and restore the athlete to full function. If not, surgery is another option.