Question regarding IR

I was thinking about this question, specifically Eric Shelton. Lets say someone goes on IR at the beginning of the season, but by this point their nearly healed. They weren't healed early enough to have been able to make a difference this season, hence them being on IR, but at this point their in decent shape. Are they allowed to work with the practice squad? Or is the field off limits? I know they can sit in meetings, but are any on field activities allowed, even is out of pads?

 

No field activity.