Football: What we've learned; what's left

Twelve of 15 spring practices are officially in the books for USC, and three remain this week including Saturday's spring game before the Trojans officially shut things down for the summer. With that in mind, here are three things we've learned so far this spring, with three things that haven't been answered yet following it. Keep in mind that what we've learned isn't limited to positive attributes of this Trojans team, and, likewise, what's still left to learn could turn out to be exceedingly positive:

What we've learned

1. USC doesn't lack, in any way, in running back talent

Four Trojans runners could probably get 15 carries a game next season and be successful: presumptive starter Marc Tyler, sophomore Dillon Baxter, redshirt freshman D.J. Morgan and the formally-academically-ineligible Curtis McNeal.

The only question at that spot, really, will only be how to divide the carries between the four. Tyler is a reliable sort who could definitely serve to improve his fitness, Baxter the somewhat-experienced-yet-so-far-underwhelming talent, Morgan the fastest of the bunch and McNeal essentially a poor man's Jacquizz Rodgers as a quick, agile scat back.

Talent at receiver might not be as good as originally projected, but running back is, it seems.

2. Matt Barkley is going to be just fine

No, Barkley hasn't had the best spring. And he probably has slightly underachieved on some of the public expectations for him over the last month. But most of that can be attributed to the players around him.

We'll get more into the offensive line in a bit, but the group's lackluster performances have harmed Barkley, surely. Still, save for a few interceptions he'd like to have back, Barkley has been solid for the duration of the spring. He and sophomore receiver Robert Woods have one of the nation's best QB-to-receiver connections brewing in spring practice, and he has worked well with tight end Rhett Ellison and some of his other offensive targets.

But as far as the rest of the season goes, Barkley will continue to be just fine. But for him to be a national player of the year candidate, as some are projecting, his weapons need to develop.

3. Young players will play big roles

Coach Lane Kiffin has talked about it all spring: the class of 2010 is going to be a huge part of this year's Trojan team, with players like Morgan, linebacker Hayes Pullard and tight end Christian Thomas expected to contribute significantly. It could also go beyond 2010, though, into the class of 2011.

Fullback Soma Vainuku will probably start. At least he's here in the spring, though. One of the incoming freshmen offensive linemen, Cyrus Hobbi and Aundrey Walker, will probably end up starting in the fall, too.

You get the sense that when Kiffin praises the two recent recruiting classes, he's also giving himself a bit of indirect praise. The recent recruits look good in practice, and they look as if they're going to play -- a lot.

What's still left to learn

1. How much of an influence will injuries have on the construction of the front seven?

Six of the seven expected starters entering into the spring at defensive line and linebacker have missed most of the spring, with Wes Horton, Christian Tupou, Armond Armstead out on the line and Chris Galippo, Devon Kennard and Shane Horton out in the linebacking corps.

That means tons of backups and walk-ons have been playing, and it means the Trojans will have to assemble their starters at those spots a lot quicker than they'd probably like to in the fall.

Horton and Tupou's injuries are short term; Armstead's status is questionable for the fall after his March hospitalization because of chest pains. Galippo, Kennard and Horton should all be safely back for fall, but, again, their lack of availability for spring could end up hurting them in the long term.

2. Do the Trojans have enough talent/depth on the offensive line to allow Barkley to succeed?

Actually, this is getting scarily close to something we've already learned, but we'll give the Trojans the benefit of the doubt and leave it as an unanswered question for the time being. But let's put it this way: of the six scholarship linemen practicing this spring, Kiffin said last week he could see only one of them starting come fall: left tackle Matt Kalil.

Barkley has stayed away from really criticizing his line this spring, but it has been fairly easy to hear the frustration in his voice after certain performances that appeared to be harmed by the lack of cohesion and talent in front of him.

It's safe to say the line could be the Trojans' downfall.

3. Are there true ballhawks and playmakers on the defense?

From the looks of things this spring, the Trojans do have a few big-play types on defense, from corner Nickell Robey's interception ability to defensive end Nick Perry's proven track record of getting to the quarterback. Safety T.J. McDonald also makes plays from time to time, but that's about it so far.

USC's defense is chock-full of steady players but lacking in risk-taking talent. A good example of that is nose tackle Tupou -- or weakside linebacker Galippo -- who is a good run-stopper but not much of a pressure-provider on quarterbacks.

This was an issue all season long in 2010, and it could be an issue in 2011, too.