I personally think it would be a mistake for him to play in 2010. He needs a redshirt year to get his head screwed on properly. He would have had to sit out a year somewhere else anyway, so this shouldn't be an issue. It would give him the proper time to set his priorities and work ethic.
I disagree a little. I think if he has made the commitment to come back and play, you need to get him into the mix. I don't think giving him time to think about things is very good idea. If he is DEDICATED to playing and to his team, I say get him in there so he knows what he is fighting for. After all this if he is not giving his team the effort he should be then sit him, redshirt, whatever.