Platelet Injections

Blood platelet injections for rapid healing... what do you know about them?

I have a minor tear or damage (6mm) to my rotator cuff. The doc doesn't think surgery is needed. It will heal in time. But... if I want to use it sooner than latter I can have my own blood drawn , spun and the concentrated blood platelets injected in the damaged area. They (the mysterious "they) indicate that one injection may be enough. But another can be given if in four to six weeks if its not better.

Anybody heard of this before?