INDIANAPOLIS -- The Indianapolis Colts are in Week 2 of their training camp and the closest Andrew Luck has come to being a participant was over the weekend at Warren Central (Ind.) High School.

That was when he wore his customary red non-contact jersey on the sideline before taking it off and joining the rest of the injured players for rehabilitation work.

When Luck (shoulder) will come off the physically unable to perform list and start practicing remains one of the biggest mysteries in the NFL. General manager Chris Ballard said two weeks ago that Luck was put on PUP with the intention of being taken off it before the regular season begins.

Luck would have to miss the first six games if he's on PUP at the start of the regular season. But the longer he remains out, the more questions emerge about whether he'll be available for Week 1 against the Los Angeles Rams.

How is Luck doing with his rehabilitation? How long will it take for him to get his rhythm down once he returns? Will the Colts still have him on a pitch count (limit his throws) during practice? We don't know the answer to any of these questions.

Coach Chuck Pagano didn't sound overly concerned after practice on Tuesday, however. Scott Tolzien, who has been inconsistent so far in camp, is the current starter.

"We are where we are with that," he said. "There's no timeline. When they say he's healthy and ready to go, we'll get him out there. He's played a lot of football."