I had the surgery and was out about 4 months until I was back to normal. I did not drop ball weight when I resumed bowling and it will hurt like hell.

I have had my right shoulder rotator cuff repaired twice.  Both surgeries were done in early January and I was back bowling regular by April 1st.  Each time I started back using a 14lb. ball for about 3 to 4 weeks, gradually going from 1 or 2 games to 3 or 4 per practice session.  When I started practicing I was at about 12 to 13 mph hour and gradually working my way back to my normal 15 mph.  I was back using my 15 lb ball about 4 weeks into my practice sessions.  Initially, there was some pain after bowling, but gradually it subsided.  The best suggestion I can give you is to do the re-hab religiously and you will recuperate in a timely fashion.  I was fortunate to have the same physical therapist both times.  He was great and pushed me.