“What does a physical therapist do for sports injuries?”

You apparently suffered soft tissue strain with jammed-up muscle/fascia tissues. They must be untangled to restore strength/function with no more pain. Any treatment (medications of any kind, heat, cold, electrotherapy, massage, stretching, manipulation, exercises of any kind, etc.) not untangling the injured tissues has no therapeutic effect. It is like untangling tangled hair, nothing works but simply combing through it. Physical therapy is not only ineffective but also may worsen the injury. No external means can effectively untangled the inured/tightened tissue but internally by the body itself via light touch (Touch-and-Hold Method) to initiate self-healing. It takes less than few hours to recover. It is detailed in my website: NoMorePainClinic.com and my book "No More Pain  All Pain Considered - A Breakthrough".       

A sport related leg injury should be evaluated by an experienced physician based on how and when the injury occurred, the associated symptoms and signs to determine the nature of the injury and therefore a clear diagnosis. A therapeutic program will then be established for physical therapist to carry out. The program may include modalities, joint range of motion, and therapeutic exercises to decrease pain and swelling, maintain functional joint range of motion, muscle strength and endurance, and functional restoration.

Usually rehab the muscles.