You are correct, he signed, commited, and is all set. I'll use the disclosure I always do when talking with kids...this is subject to change (or possibly be inaccurate) - as they are 17 year old kids.
Anyways, I spoke with Joey right before Coach Brewster's talk at the Signing day social. He told me that he was going to grayshirt next year (I can't remember if Brew mentioned that) and he would be on campus next January, 2010. I asked him why, and he just said that's what scholarship he was given. I did ask him about his ACT, since people had questioned his admittance, and he said he had not gotten his score back yet. He does seem very excited to be a Gopher, and can't wait to get out there!