Methods and device for treating or healing an injured tendon or ligament is disclosed. The device, a tendon and ligament repair sheet, has a porous layer and a denser layer, and optionally a therapeutic agent in the porous layer, the denser layer or both. The repair sheet is made from a resorbable or non-resorbable polymer. The repair sheet is securely attached to the injured tendon, ligament, muscle, or bone and has a suture pull out strength of at least 3N. If the injury involve severing of a ligament or tendon, one should place the severed ends in close proximity to each other and securely attach the repair sheet to both sides of the severed tendon or ligament at a distance from the injury so that the repair sheet remains securely attached to the tendon, ligament, muscle, or bone while the tissue is healing.