Prevention

Rotator cuff injury can be prevented by correctly and regularly stretching however to find the most effective treatment plan a consultation with a physiotherapist is recommended (especially for athletes with higher risk of injury). Also when performing repetitive motions doing so in proper form or wearing a brace.

Stretches

Stretching can reduce the risk of injuring or tearing the tendons surrounding the rotator cuff. This can strengthen the muscles surrounding the area to prevent injury. 
It is important to strengthen the shoulder and shoulder blade as well as the mid back muscles. 
Learn more about the importance of preventing rotator cuff injury from the Mayo Clinic.