Ht., Wt.: 6-1, 170
Why he'll contribute: Aaron Colvin is the Sooners' only experienced cornerback returning, so Moore will absolutely have every opportunity to play an immediate role. Walk-on Brandon Young worked as a second-team corner in the spring game, drawing attention to the unit's depth issues.
Why he might not: If sophomore Cortez Johnson, who sat out last year after transferring from Arizona, takes firm control of a starting spot opposite Colvin, Moore won't have much of a chance to make a big, immediate impact.
QUINCY RUSSELL, JR., DT
Ht., Wt.: 6-3, 311
Why he'll contribute: Russell should immediately compete to play on Oklahoma's thin, inexperienced defensive line. Every significant contributor at defensive tackle last season was a senior, and sophomore Jordan Phillips remains a raw talent.
Why he might not: Russell signed with Texas out of high school, but academic issues forced him to take the junior-college route instead. There remains some question about whether or not he's actually qualified for OU yet.
JOSIAH ST. JOHN, JR., OT
Ht., Wt.: 6-6, 305
Why he'll contribute: Oklahoma enters 2013 dangerously thin depth-wise at the offensive tackle spots. Starters Daryl Williams and Tyrus Thompson are both very experienced, but there isn't much help backing them up. St. John should provide some insurance there right away.
Why he might not: St. John wasn't an early enrollee, and — as with any newcomer — there's always the possibility that immediate contribution is too much to ask. Coaches will definitely need St. John, though, whether his role on the 2013 line is big or small, and they'll need him to be a quick learner.