Conference expansion forced a shift in focus, but now we are back to discussing who the studs on the field will be in 2010 instead of where the studs will play in 2011. We will continue the position-by-position breakdown for the next two weeks and then transition into a look at what the season holds for the Pac-10.

We have talked about almost all of the skill players, and the guys that go and up and down the field, but now it is time to talk about the guys fighting the battle in the middle, so the fast guys can do what they do.

The offensive linemen are often the unheralded members of the football team, but without them nothing could happen at all. These guys open the massive holes you see on Saturdays when the backs shoot through the line, and contrary to reputation are usually the guys with the best SAT scores on the field.

Click here for the best iPhone app for college football. Stats, rosters, schedules and more.

These guys absorb all the initial hits on the line so that the speedsters and guys with rocket arms don't have to take the blunt shots. Sure, they let a few through, and that is when you hear about them. But these are still the guys who protect a team's Heisman candidates. It is not coincidence that the second-highest paid player on any pro team behind the quarterback is usually the left tackle protecting him.

The Pac-10 is loaded with prospective NFL offensive linemen. The real trick, and this is tough to do, is for each team to mold those players into a cohesive unit before the season starts. Let's take a look at the lines across the conference:

Oregon

Returning all five starters from a Pac-10 championship team can never hurt. The Ducks led the league in rushing offense last year with 231 yards per game. It would be a safe bet that Chip Kelly is going to turn to LaMichael James and Kenjon Barner t for more big holes to run through, especially with a new quarterback under center. .

The rest of the Oregon offensive line cast is solid and is the best returning group out west. Having Rimington Trophy watch list center Jordan Holmes and Lombardi Award watch list guard Bo Thran just adds to the Duck’s rushing opportunities. The line will keep the Ducks in contention for a national title if the quarterback situation plays out well for the team.

USC

The Trojans return three of the five starters from last year's squad. As of right now tackle Tyron Smith, center Kristopher O'Dowd and guard Butch Lewis will continue to protect Matt Barkley, but who knows if any of those guys will bolt because of the sanctions brought down on USC. It is highly unlikely, but you never know.

O'Dowd and Lewis were co-starters last year, so only time will tell what they will do with all the snaps in their favor. USC lost three key players off a line that averaged 166 yards on the ground and 222 through the air last year. Smith, O'Dowd and Lewis will have to step up and lead a small group of linemen without much playing experience.

Arizona

Outland and Rimington Trophy watch lister Colin Baxter leads a talented line into battle each week for the Wildcats. Arizona has the tools coming back to vie for the Pac-10 crown, but a lot will depend on the line producing like they did last year. The Wildcats finished off an 8-5 record and the No. 3 passing and No. 5 rushing offense in the conference. The cohesiveness should be solid with the offensive line after losing only one starter in tackle Mike Diaz.

Arizona State

The Sun Devils were in desperate need of offensive linemen who could start immediately, and they got just what they needed in junior college transfers Brice Schwab and Chris DeArmas. It will be interesting to see if ASU can improve upon a poor season last year. A lot of the troubles the Sun Devils encountered were because of the offensive line. Noel Mazzone is the new offensive coordinator, so it should be interesting to see what happens with the offense.

Oregon State

Alex Linnenkohl is not the only constant on the Beavers line, but he is the only one on the Rimington Award watch list. The Beavers will look to build on what they formed last year. The unit returns four starters, and the only battle is at right guard. Some shifting could alleviate that problem, but it would put one of last year's starters at a different spot.

The rest

Chase Beeler of Stanford and Kai Maiava from UCLA round out the six-member group of Pac-10 centers on the Rimington Award watch list. Jonathan Martin should be a rock for Stanford, and has made the Lombardi Award watch list along with Beeler, O'Dowd Thran.