The Vikings lost quarterback Christian Ponder to a concussion, long before they went on to win 23-20 in overtime after each team missed a kick.
Ponder took a hit to the head late in the second quarter Sunday against Chicago during a rushed third-down throw.
Ponder was pressured and knocked down by defensive end Shea McLellin and linebacker James Anderson. Ponder was slow to get up and looked a little woozy as he walked off.
Ponder took three sacks in the first half and completed just three of eight passes for 40 yards. Matt Cassel came in for the final drive of the second quarter, to a rousing cheer from the crowd.
Browns quarterback Brandon Weeden was diagnosed with a concussion after Cleveland's loss to Jacksonville, though he played the entire game.
The Browns also temporarily lost wide receiver Josh Gordon to a head injury, but he returned for a record-setting day.
Gordon had his helmet knocked off by Jaguars safety Winston Guy as he attempted to make a leaping catch near the sideline.
Gordon's head snapped back as he landed and he appeared to hit it on the hard ground. He walked off the field under his power, and after being examined on the sideline, he was taken to the locker room for further evaluation.
Gordon returned just before the end of the third quarter and finished with 10 catches for 261 yards and became the first player in NFL history to record 200 yards receiving in consecutive games.
Broncos wide receiver Trindon Holliday left with a shoulder injury while the Chiefs lost tight end Anthony Fasano to a concussion and left tackle Branden Albert to a knee injury.
The Broncos also lost wide receiver Demaryius Thomas for several series in the first half with a shoulder injury. Thomas returned to the game just before halftime.
Holliday, who also returns punts and kicks for the Broncos, was hurt in the first half and did not return.
Fasano sustained his concussion when he slammed his head into the turf in the third quarter, and Albert left after hurting his knee early in the fourth quarter.
Albert, the Chiefs' franchise left tackle, was replaced in the lineup by No. 1 overall pick Eric Fisher, who had been starting at right tackle. He's been dealing with a shoulder injury and was active for the game, even though he did not start.
In Charlotte, N.C., Tampa Bay cornerback Darrelle Revis left the Buccaneers' game against Carolina in the third quarter with a shoulder and chest injury and did not return. He will be evaluated on Monday.
He attempted to intercept a pass by Cam Newton near the sideline. He was attended to by the medical staff but was able to walk off the field under his own power. He was looked at briefly on the bench and then taken to the locker room for more observations.
49ers left tackle Joe Staley injured his right knee early against St. Louis and didn't return.
St. Louis left tackle Jake Long went down late in the third quarter. Staley was hurt at the 11:13 mark of the first quarter when he landed awkwardly while grabbing his knee. Staley stayed on the ground for several minutes before walking off the field on his own.
New York Jets kick returner-wide receiver Josh Cribbs left with a shoulder injury. It was uncertain when Cribbs was injured, but the team announced the injury late in the second quarter.
The Titans lost two more tight ends. Delanie Walker left with a concussion in the first quarter and Collin Mooney was taken by golf cart into the locker room with what appeared to be a left leg injury in the second half. Colts defensive tackle Ricky Jean Francois (sprained foot) and running back Daniel Herron (strained pectoral) should have MRIs on Sunday night, coach Chuck Pagano said.