Bartolo Colón active players as of June 11, 2008. Colón did not pitch in 2010 due to ongoing right shoulder and elbow pain and damage to the rotator cuff, ligaments and tendons. In March 2010, he received a transplant of stem cells to repair the damaged tissues in his right shoulder. The orthopedic surgeon who performed the surgery said he had used human growth hormone in previous surgeries of the same type but not with Colón. The surgery was scrutinized by MLB but no wrongdoing was found. Colón then played in the Pre-World Championship in Puerto Rico, winter ball with the Aguilas
Rotator cuff arm, moving it outward and away from the trunk, the rotator cuff compresses the glenohumeral joint, an action known as concavity compression, in order to allow the large deltoid muscle to further elevate the arm. In other words, without the rotator cuff, the humeral head would ride up partially out of the glenoid fossa, lessening the efficiency of the deltoid muscle. The anterior and posterior directions of the glenoid fossa are more susceptible to shear force perturbations as the glenoid fossa is not as deep relative to the superior and inferior directions. The rotator cuff's contributions to concavity compression and