I would listen to knott (and your doctor/pt) on this.

what about a stationary trainer or spin class with your arm immobilized for now? i shattered my scapula a couple of years ago and the trainer w/an immobilizing sling kept me fit til I could ride again. and that first ride was vomit inducingly painful - every slight bump. dont over do it. your injury actually has alot worse downside and possible lasting effects than mine. my shoulder crackles like popcorn now and I cant keep a bra strap up on that side. you could end up with redislocation or worse. be careful.