The line of scrimmage will be hotly contested in the Pac-12 in 2013.

We believe the Pac-12 will be strong on defense next fall. Nine teams have at least seven starters coming back on defense, and the star power is impressive, topped by certain All-Americans in UCLA OLB Anthony Barr and Arizona State DT Will Sutton, a consensus All-American in 2012.

But the guys getting in their way should be up to the task. In fact, the most improved position group in the Pac-12 in 2013 should be the offensive line.

The only team that doesn't welcome back at least three starters on the line is Utah, but a big story in Salt Lake this spring has been how good the Utes' O-line has looked.

Seven teams welcome back four starters, compared to just two (Arizona and USC) a year ago. Moreover, just about every team offers up some star power, established or budding.

No team will exit the spring with serious concerns -- at least in terms of overall team priorities and uncertainties -- on the O-line, though Colorado and Washington State still are questionable, despite four returning starters each, due to yielding 52 and 57 sacks and run blocking poorly a year ago.

There were no returning first-team All-Pac-12 linemen in 2012. This year there are three, including Morris Trophy winner David Yankey of Stanford and UCLA's Xavier Su'a-Filo. Both are likely preseason All-Americans, and they might get joined by Oregon center Hroniss Grasu, who was first-team all-conference as a sophomore.

Last year, Arizona State, Oregon State, UCLA, Utah and Washington State entered 2012 with major offensive line questions. Washington joined that group when it was hit by injuries. Stanford was in question because of the departure of All-Americans David DeCastro and Jonathan Martin.

This year? Stanford might have the nation's best offensive line, and no team appears on a downtick. Arizona State, Oregon State, UCLA and Washington are projecting major improvement on the O-line.

The Pac-12 blog believes the conference could be lining up for an extremely strong season. Oregon and Stanford are top-5 teams. UCLA, Oregon State, Arizona State, USC and Washington look like potential top-25 teams. The patsy level -- California, Washington State and Colorado -- shapes up to be considerably improved.

Why?

Better defenses, better offensive lines and the best lineup of quarterbacks in the country.