Threaten me with a good time

I had a text exchange with a manager at work, getting ready to go back to work next week. I asked what I might need to do if the doctor would not approve me for full duty, and was informed that I could apply for light duty, but that it might not be approved. Of course I had to ask what the other option would be - I stay out of work entirely until I can come back full duty?

Yes.
...
...

Oh dear.

Of course there is the concern that if I were out for three straight months I would have to take tests before I was allowed to go back to work, and that if I failed those test I could lose my job. I can't imagine I could possibly take two more months to be ready for lifting 50lbs.