I really can't see any of the LBs, WRs, or most of the DBs cracking the rotation, unless they're needed on Special Teams.
Tressel has showed that he will play true freshman on the OL (Sims & Mangold in '02), so I'd look for Person, Mitchum, Rehring, and Skinner to get serious looks for some playing time.
Also, the staff has liked to rotate a lot of guys on the DL for the last couple years, so Abdallah, and Barrow have a chance to play, IMO.
As for Ginn, I don't care if he sees a snap at DB this year or not. As long as he can add explosiveness to the KR game and take an occasional trip to the House, that's good enough for me. OSU has been awful in this regard the last few years. We need a threat desperately.