The two quarterbacks from last season's Super Bowl left their games after taking blows to the head Sunday.
The Steelers' Ben Roethlisberger wobbled off the field during overtime of Pittsburgh's 27-24 loss to the Chiefs, while the Cardinals' Kurt Warner went out in the second quarter of Arizona's 21-13 win over the Rams.
Roethlisberger had thrown for 398 yards and three touchdowns when he apparently took a knee to the helmet while being sacked by Derrick Johnson and gave way to Charlie Batch. Coach Mike Tomlin said he was not certain how severe the injury might be.
"He took a blow, needless to say, it was a concussion-oriented thing so I doubt he was going to come back into the football game," Tomlin said. "I don't have a lot of information in terms of where he is or his level of availability. We will have more information as we proceed."
Warner was 15-for-19 for 203 yards and two touchdowns, helping the Cardinals take a 21-3 lead. It appeared Warner was hurt by safety O.J. Atogwe's high hit on a blitz that drove the quarterback's head into the turf. Warner lay on the field for a few seconds before getting up and stayed in the game for the last six plays of a 90-yard drive.
Matt Leinart replaced Warner late in the second quarter. Warner said it was just a precaution for what the team termed concussion-related symptoms
"I felt pretty good coming out right after halftime, but I just wanted to be smart," Warner said. "It was one of those situations where I didn't feel perfect."
St. Louis quarterback Marc Bulger said he took a blow to the head on the team's final possession, apparently on a sack by Darnell Dockett, and will undergo evaluation Monday. Like Warner, Bulger said his head had cleared after the game.
The Steelers, already missing Pro Bowl safety Troy Polamalu (knee), also lost guard Chris Kemoeatu to a right knee injury.
Two other quarterbacks played through injuries to throw for game-winning touchdowns.
Lions rookie Matthew Stafford was able to return to the game because the Browns called a timeout after he hurt his left shoulder on what would have been the last play. Detroit was given an untimed play because of a pass interference call in the end zone when Stafford heaved a desperation attempt.
Stafford was hit after his throw to the end zone and replaced by Daunte Culpepper. He came back to throw his fifth touchdown pass from one yard to Brandon Pettigrew for the 38-37 win.
Coach Jim Schwartz said X-rays showed Stafford's collarbone wasn't broken, but added more tests are needed.
Before and after every snap, the Cowboys' Tony Romo felt the throbbing in his back, the result of an accidental blow while making a first-quarter tackle.
Romo scrambled for a first down, then completed seven straight passes, the last a 10-yarder to Patrick Crayton for a touchdown with 2:41 left that gave Dallas a 7-6 victory over the Washington Redskins.
After Marion Barber's fumble, Washington's DeAngelo Hall recovered and Romo brought him down. As Hall was falling, his knee conked Romo in the back. Romo was so bad after that it was obvious something was bothering him.
Redskins running back Ladell Betts, the fill-in for injured Clinton Portis, damaged the MCL in his left knee midway through the first quarter. Coach Jim Zorn said Betts will have an MRI to determine the severity of the injury.
Right guard Chad Rinehart fractured his right leg early in the third period. Rinehart was taken off the field on a motorized cart with his lower leg in a brace after it was rolled on by Cowboys linebacker Anthony Spencer.
The Buffalo Bills are even more banged up after losing 18-15 to the Jacksonville Jaguars.
Running back Marshawn Lynch (shoulder), guard Eric Wood (leg), guard Seth McKinney (knee) and defensive tackle John McCargo (calf) left the game and did not return.
Wood appears to be the most serious of the group. He broke his left leg on the second play of the fourth quarter and will remain in Jacksonville overnight.
The Bills already were playing with a shuffled offensive line. Lynch was taken to the locker room on a cart in the second quarter. He was on the sideline in the second half in street clothes.
The Green Bay Packers lost two cornerstones of their defence during a 30-24 victory over San Francisco and could be playing without them for a lot longer.
Coach Mike McCarthy said the knee injuries to cornerback Al Harris and outside linebacker Aaron Kampman "did not look very good" and were cause for concern.
McCarthy said the team would have more definitive information Monday.
It could be a serious setback for a defence trying to keep the Packers (6-4) in the thick of the NFC wild-card race. Teammates already were pondering a future without Harris and Kampman.
Harris was injured early in the fourth quarter and was carted to the locker room. While on the cart, he pulled his sock down and tried to brace his left knee; the team did not identify which knee was injured.
Kampman also appeared to hurt his left knee, which buckled on a play in the third quarter. Kampman walked off the field with a limp, then headed to a cart and was taken to the locker room.
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