Nagging questions dog nation's top college football teams heading into summer

QB Braxton Miller should be a great fit for Urban Meyer's version of the spread. And Meyer's first Buckeyes defense should be one of the dozen or so best in the nation. But outside of Miller, the offense is questionable because of a startling lack of proven playmakers. Quite simply, there aren't any. The receiving corps looks especially barren. The offensive line lost three starters and also has to adjust to a new blocking scheme. The schedule is kind in that each of the first four games is at home, though there is a visit from California that will test the Buckeyes. Game 5 is at Michigan State on Sept. 29. The Buckeyes lost 10-7 to Michigan State last season, and it could be more of the same this season.

The Hokies lost their top two tailbacks, four starting linemen and their top two receivers. At least QB Logan Thomas returns. The rushing attack always is important for Virginia Tech, and that is the biggest issue. TB J.C. Coleman enrolled early and had a good spring, but the Hokies missed Tony Gregory, who had a knee injury. Coleman, Gregory and Michael Holmes are the contenders for the job. There isn't much time for working out the kinks: The Hokies open with a key ACC division game against Georgia Tech. A big positive is that the Hokies' defense looks primed to be one of the two best in the league. Despite the offensive holes, Virginia Tech will be the favorite in the ACC's Coastal Division. But it's hard to see the Hokies winning the league title unless the offense produces numbers similar to last season (413.0 yards per game).

QB Kirk Cousins is gone, as are the top three wide receivers; no returning wide receiver caught even five passes last season. Given that four starting linemen and a nice group of tailbacks is returning, Michigan State seems likely to count on the run more than usual this season. The defense is good enough to win the Big Ten, but it will be put to the test in September. Michigan State doesn't have any time to ease into the season. The opener is against Boise State. Game 3 is Notre Dame. And Ohio State comes calling in Game 5, on Sept. 29. The Spartans play back-to-back road games in late October against Michigan and Wisconsin. They won't win both if their offense is too one-dimensional.

FSU struggled to consistently run the ball last season, averaging just 112.2 rushing yards per game (104th nationally). There is a nice group of tailbacks and QB E.J. Manuel can be a dangerous runner, but the line remains questionable. As with a couple of teams we've already mentioned, FSU's defense is going to be stout. But for Florida State to live up to what are going to be lofty preseason expectations, the Seminoles need to add about 40 to 50 yards to that per-game rushing total over last season.

The Badgers benefited from a quarterback transferring in from an ACC school last season, as former North Carolina State star Russell Wilson guided them to the Big Ten title. They're hoping for more magic from an ACC transfer this season. Former Maryland starter Danny O'Brien will arrive over the summer, but Badgers fans shouldn't be expecting a case of déjà vu. The biggest reason? O'Brien isn't nearly as good as Wilson. There is good surrounding talent, most notably TB/TD machine Montee Ball, WR Jared Abbrederis and a big, physical line. The run defense should be better than it was last season, when Wisconsin allowed 152.8 rushing yards per game (60th nationally), and that will help O'Brien's cause. Still, there's going to be pressure on him. Can he throw 20 or so TD passes and avoid mistakes? If "yes," the Badgers could win the Big Ten again. If he struggles, though, the Badgers won't even win their division.

The Longhorns' passing numbers have steadily decreased, from 299.5 yards per game in 2008 to 273.6 in '09 to 232.0 in '10 and finally to 189.9 (86th nationally) last season. Granted, the rushing attack did improve last season over 2010's paltry totals, and it improved without much of a passing threat. Still, Texas isn't going to win the Big 12 with an unbalanced offense. The question is whether the receivers are just OK or whether the quarterback issues of the past two seasons have cut down on the receivers' abilities to make plays. Sophomore David Ash and junior Case McCoy are vying for the quarterback job, and coach Mack Brown has said he won't name a starter until fall drills. If Texas throws the ball this fall as poorly as it did last season, it's going to lose at least four games. That would be 16 losses in a three-year stretch, and you wonder if Brown would come back in 2013 in that scenario.

Alabama won the national title in 2009, then lost three starters in the secondary. The new-look defensive backfield struggled in 2010. Alabama won the national title in 2011, then lost three starters in the secondary. Will a rebuilt secondary struggle this fall? CB Deion Belue, a junior college transfer who enrolled in January, had a solid spring and could end up as a starter. S Vinnie Sunseri, the son of former Tide linebacker coach Sal Sunseri, who now is coordinator at Tennessee, also looked good during spring ball and could wind up in the starting lineup. Still, the only proven commodity in the secondary is FS Robert Lester, the lone returning starter. But he played better in 2010 than he did in 2011. Dee Milliner, who was the nickel back last season, almost surely will start at one corner spot. The secondary will be tested early: The Tide opens against Michigan, then plays Arkansas in Game 3.

This season will serve as a test for coach Chip Kelly, whose Ducks lost their starting quarterback (Darron Thomas, who turned pro early but wasn't drafted), their starting tailback (LaMichael James), their leading receiver (Lavasier Tuinei, who had 10 TD receptions), a productive tight end (David Paulson, who scored six times) and two starting linemen. The Ducks look to have able replacements at tailback, receiver, tight end and along the line. That leaves quarterback. Bryan Bennett played well when Thomas was hurt last season, and redshirt freshman Marcus Mariota played well enough this spring to lend some intrigue to the fall-camp competition at the position. Oregon's defense should be noticeably better than it was last season, so if the offense comes close to matching last season's production, the Ducks will be just fine. USC will go into the season as the Pac-12 favorite, but a tremendously favorable schedule - the Ducks don't play a road game against a team that went bowling last season until mid-October - should give Kelly and his offense ample time to get the kinks out.

The Tigers averaged 152.5 passing yards per game last season; that ranked 106th nationally. Only three teams with winning records threw the ball for fewer yards per game. Despite a one-dimensional offense, LSU played for the national title. The rushing attack is going to be good again; so is the defense. So imagine what just a slight bump in passing yards, say 50 more per game, could do. Strong-armed Zach Mettenberger is going to be the starting quarterback, and there are those anointing him as a messiah of sorts. But let's get serious. Mettenberger enrolled in January 2011 out of junior college and went through spring ball. Alas, he couldn't beat out either Jarrett Lee or Jordan Jefferson, and played in five games as the third-string quarterback last season. Again, though, Mettenberger doesn't need to make like Bert Jones or Y.A. Tittle, two former Tigers stars. If he can just be mediocre as a passer, LSU easily could end up playing for the national title again.

USC has the offensive backfield, receiving corps, offensive line, linebackers and secondary necessary to win a national title. The only position group that is a question is the defensive line, specifically the tackles. Both starting tackles from last season are gone, and there is precious little experience at the position. Sophomore George Uko has a high ceiling and could contend for All-Pac-12 honors this fall, but no other tackle has done anything. The first two games (Hawaii, Syracuse) are gimmes, but then the Trojans travel to Stanford for Game 3. The Cardinal are going to be especially run-heavy, which means the Trojans' defensive line will have to be in "prove it" mode early on. There also are tough early-season matchups with Cal, Utah and Washington.