Defensive tackle: (18 starts) This position is one of the Sooners' biggest question marks, but Stacy McGee is a returning starter. Casey Walker and Jamarkus McFarland also started a handful of games. The defense could really be good if a freshman or two emerges early in the season.
Defensive end: (26 starts) Frank Alexander, hampered by an ankle injury, lost his starting job midway through last season, regrouped to return to the starting lineup and is the most experienced player on the D-line. Ronnell Lewis gained "starting" experience after moving from linebacker. David King started a handful of games. R.J. Washington and other young players will provide depth.
Linebacker: (50 starts) Travis Lewis returning for his senior season, gives the defense an anchor; a player who has 362 career tackles and at least 109 tackles all three seasons. Tom Wort was overwhelmed early when pressed into a starting role but was much improved late in the season. Sophomore Corey Nelson hasn't started a game, but coaches said he had the best spring of anyone on the roster.
Defensive back: (51 starts) A huge question mark last season turned into a strength. Cornerbacks Demontre Hurst and Jamell Fleming were solid as first-year starters. Second in the nation in passes defended, Fleming missed spring drills because of academic issues but has returned. Aaron Colin, who made only one start, moves to safety. Nickel backs Tony Jefferson and Joseph Ibiloye both started last season.