Five questions for the New Year, No. 4: How will USC replace Jurrell Casey and Tyron Smith?

Every day until Friday, we’ll tackle one key question facing the USC football team in 2011 and attempt to answer it logically. Feel free to leave your potential answer in the comments section each day.

Wednesday's question involved the sanctions' likely effect on 2011 recruiting class. Today, we present the fourth of our five questions: Who will replace the two departed players for the NFL at DT and RT? Will they be able to approach Jurrell Casey and Tyron Smith's effectiveness?

USC had two players named to the All-Pac-10 First Team -- defensive tackle Jurrell Casey and right tackle Tyron Smith.

How fitting it is, then, that the two are the Trojans' only two players to choose to depart school early and enter the 2011 NFL Draft. But such is life when you're dealing with talented junior players, and, although both players had said they were 50-50 on their decisions after the season finale, it's certainly not a head-scratcher to see both of them decide to go.

Now, the question is this: How do you replace your two best players who you hadn't counted on losing?

There's no easy answer, and, especially in Smith's case, there may be no answer for a long while. But finding reasonable solutions at both positions, sooner rather than later, is key to USC's 2011 success.

First, Casey.

You can say a lot of good things about what Casey did in 2010: He was the only Trojan to not have a bad game; he switched positions between nose guard and under tackle willingly as the coaching staff's opinions of his peers changed; he even turned up his performances some as the season went on and terrorized UCLA's offensive line in the season finale.

But you can also say a lot of good things about his likely replacement, senior Christian Tupou, who missed the entire 2010 season after tearing ligaments in his left knee in May. Tupou had started for two seasons at nose tackle for USC and was expected to man the position again in 2010 alongside Casey. His injury set into motion various attempts by the staff to fill his role, something they struggled with for a good portion of the season.

They tried DaJohn Harris at nose and Casey at under early on, then tried Armond Armstead at under and switched Casey to nose, then switched Harris back to nose and Casey back to under later on in the year. Confusing?

Indeed. And it might be more of the same next season. Harris and Tupou are both natural nose guards, and Armstead is the only experienced player who fits well at under tackle on the roster. Redshirt freshman George Uko will also be a possibility, but the point is that there will probably still be some flip-flopping at the two spots next season.

As for Smith's right tackle spot, the easiest way to see what Smith meant to the team this season is to examine what happened to the offensive line in his absence against Notre Dame.

In short, they were dismantled. Badly. By an average Fighting Irish defensive line.

When he returned the next week against UCLA, the USC offensive line miraculously looked a whole lot better. Smith was the glue all season long, and he was similarly effective as a sophomore in 2009.

Butch Lewis replaced him against the Irish and did OK. He'll be gone in 2011. Who could replace Smith next season?

Well, it was supposed to be Aaron Douglas, until the junior-college player and former Kiffin lineman at Tennessee chose Alabama over USC earlier this month. Now, the consensus answer is Kevin Graf, although the redshirt sophomore will be coming off shoulder surgery. He also might be better suited to playing guard, and the Trojans will also need to find a replacement for left guard Michael Reardon if the fourth-year junior ends up not returning for his fifth year, as he is reportedly considering, and for right guard Khaled Holmes, who is expected to move to center to replace outgoing senior Kristofer O'Dowd.

Assuming Graf ends up starting at right tackle or left guard in 2011, either John Martinez, Martin Coleman, or a freshman will have to start at the other two spots unless Reardon returns. Three completely inexperienced players starting in one offensive line is often a poorly-written recipe for disaster.

USC did sign two junior-college offensive linemen, Jeremy Galten and David Garness, to enroll in January, but neither player is believed to be of starting quality right off the bat.

So, yes, the offensive line will surely be a problem in 2011. Smith could have helped that a lot by returning, but the 20-year-old is off to the greener pastures of the NFL now, as is Casey.

And they'll both be long removed from any difficulties USC encounters in finding their replacements -- that'll be Lane Kiffin's problem.

That's it for today. Tomorrow's question for the New Year is as follows: "What role -- if any -- will Dillon Baxter have with the 2011 Trojans?"