NORMAN, Okla. (AP) -- Oklahoma linebacker Corey Nelson will likely miss the rest of the season because of a partially torn muscle in his chest.
Sooners coach Bob Stoops said in a statement Sunday that Nelson is scheduled to have surgery Tuesday for the torn pectoral.
Nelson was hurt Saturday against TCU. He is second on the team in tackles with 27. The senior team captain also had an interception return for a touchdown and a sack for a defense that ranks ninth in the country in yards allowed per game.
No. 12 Oklahoma (5-0 2-0) plays rival Texas on Saturday with first place in the Big 12 on the line.
The Sooners have typically had one of the most prolific offenses in the country in recent years, but they have been leaning on their defense more this season. It's worked out just fine.
Oklahoma has posted one shutout (34-0 against Louisiana-Monroe) and made critical defensive stops in wins over West Virginia (16-7), Notre Dame (35-21). On Saturday, Oklahoma didn't allow TCU a first down until midway through the third quarter and limited the Horned Frogs to 210 yards of offense, using stunts and blitzes to slow elusive TCU quarterback Trevone Boykin.
Oklahoma ranks sixth in the nation scoring defense, allowing 13 points per game and 10th in passing defense (168.4 yards per game).
''We take pride in defense,'' linebacker Eric Striker said. ''That should be every defense in every conference, regardless of what conference you're in, to be the best, dominant defense you can be. That's what we want to do.''
The key for the Sooners was ''to be physical,'' said defensive end Charles Tapper, who sacked Boykin twice. ''At halftime we feel like we start all over again. We have to come and be physical against them all over again. We have to keep pushing and never give up. You've got to give four quarters, just like coach (Bob) Stoops always tells us.''
Perhaps the most impressive thing for defensive coordinator Mike Stoops has been the character his players showed late in the game against both Notre Dame and Texas Christian.
''I like our team,'' he said. ''I think that's the thing that really jumps out. There's a lot of guys really playing well. I don't know if you can really pinpoint one guy. I just think it's a collective effort, and when you have collective efforts, I think that produces promising results. That, to me, seems to be the key to our success right now.
''We've got three or four impact players, but the rest of our guys are playing really solid football. We don't have many glaring weaknesses and that's a good place to be.''
It's a long way from the end of last season, when Oklahoma's defense melted down against West Virginia (giving up 778 yards), Oklahoma State (giving up 618 yards) and in the Cotton Bowl against Texas A&M (giving up 633 yards in a 41-13 loss).
''I think our players feel better,'' Mike Stoops said. ''We're accomplishing the things we wanted to accomplish here - be more flexible, be more diverse, put more speed on the field. I think that's evident every time you watch us play. Now we've got to collectively try to continue to build off what we're doing and continue to be more diversified moving forward.''
The latest dominant performance came despite the absence of starting defensive lineman Jordan Phillips, who missed the game with an unspecified injury. Nelson left the game in the third quarter and defensive back Julian Wilson later hobbled off the field with a leg injury.
Bob Stoops said he'd be surprised if Phillips didn't return for the Texas game.
Texas will be without starting quarterback David Ash, who will miss the game after continuing to suffer from concussion-like symptoms.