I've heard from people here that he'll do very light throwing, probably from around 20 feet and then call it a day. The team was planning on having him throw today. I don't know why the change, but he's dying to get out there, they say.
I believe the thinking is to do it tomorrow, during the team's first full-squad workout, because it will probably occur in quiet, with no cameras or reporters (who will all be distracted doing other stuff). Today was a quiet day in camp. It would have been the only thing talked about this afternoon. Tomorrow will be a different story...