First, it was center Ben Habern. On Monday, the Sooners lost senior guard Tyler Evans for the season.

Evans injured his right knee in practice on Friday and an MRI on Monday revealed a torn ACL. Between Evans and Habern, who had to end his career because of lingering back and neck injuries, the two seniors had 59 starts between them.

The Sooners will turn to junior Bronson Irwin to replace Evans. Irwin has not started before; he played 127 snaps last year.

"He's a capable starter," offensive line coach James Patton told the Oklahoman. "He plays hard. He's a great kid. He had a great winter and a great spring, and it looks like he carried it over."

The Sooners open the season with a UTEP on Sept. 1. The Miners had 24 sacks last season. OU quarterback Landry Jones is still confident in his protection.

"They were so deep all the way around," Jones said. "So, yeah, we lost two really dominant players, but we're still pretty set at those spots."

Other news and notes around the Big 12

For more up-to-the-minute news and analysis from Big 12 bloggers C.J. Moore and Patrick Southern, follow @CBSSportsBig12