I am currently in the same boat.
I hit a road groove on our club century last month and went down hard on my left shoulder. I went to the ER where they told me it was probably a sprain, but to follow up with an Ortho. (fortunately I have one already)
He advised that it looked like a gr 1/2 AC seperation. Keep it in a sling, limit use, stay off the bike, come back in 2 weeks for follow-up x-rays. Well, the follow-up shows a fracture on the Acromion process.
Off the bike for 4 weeks already, probably gonna be a few more. He DID approve the trainer, so I won't lose ALL my recent gains.