It was a rough day for NFL running backs.

Detroit's Kevin Jones, Baltimore's Willis McGahee, Indianapolis' Joseph Addai, the Giants' Brandon Jacobs and New Orleans backup Jamaal Branch all were banged up Sunday.

Jones' knee injury during the Lions' 25-20 win over the Kansas City Chiefs was the most severe. He caught a pass in the first half and after being tackled, immediately grabbed his right knee.

"It doesn't look good," Detroit coach Rod Marinelli said. "It's pretty serious."

Jones has been sidelined by injuries in each of his four seasons since Detroit drafted him in the first round of the 2004 draft. He was limited to 12 games last year with a foot injury, which led to him being on the physically unable to perform list during training camp and missing the first two games of this season.

McGahee broke two ribs on a hit in the first quarter of the Ravens' 27-6 loss to Seattle.

McGahee, who entered Week 16 fifth in the NFL in rushing with 1,207 yards, had five carries for 10 yards before going out.

The team said McGahee was hopeful of returning in the second half, but was announced as being out when the second half began. After the game, the Ravens said McGahee had cracked ribs and his status for next week's season finale against Pittsburgh was unknown.

Former Ute Mike Anderson took over for McGahee, but was slowed by a hamstring injury in the second half. After having just seven carries all season, Anderson had 44 yards on eight touches.

RAVENS reserve tight end Quinn Sypniewski, filling in for Todd Heap and Daniel Wilcox, sustained a concussion and bruised sternum.

COLTS: Addai played sparingly after the first quarter of the Colts' 38-15 win over Houston when he reportedly sustained back and shoulder injuries, a report later denied by Colts spokesman Craig Kelley. He said Addai was out because of a coach's decision.

After the game, Indianapolis coach Tony Dungy said Addai — and receiver Anthony Gonzalez, who bruised his foot and left in the first half — could have returned.

"Those guys are not nicked up too bad," Dungy said.

The Colts, without Marvin Harrison for the ninth straight game, also lost tight end Ben Utecht with a shoulder injury. Defensive back Tim Jennings left in the final minute with an undisclosed injury. Dungy had no immediate updates.

GIANTS: Jacobs rumbled for 145 yards and two scores in New York's 38-21 victory over Buffalo, including a powerful 43-yard run, but he went out with a sprained left ankle in the fourth quarter. Jacobs, who returned briefly after hurting his ankle, said the injury isn't major, and he expects to play next week.

BILLS Pro Bowl left tackle Jason Peters did not return after hurting his groin in the second quarter. Without him, Buffalo allowed three sacks, ending a three-game run without allowing a sack.

SAINTS: Already missing Reggie Bush with a left knee injury, Branch broke his leg on a special teams play against Philadelphia. New Orleans nearly had a more serious problem when, in the second quarter, starting back Aaron Stecker appeared to hurt his left leg and was carted to the locker room. He returned in the third quarter.

Saints quarterback Drew Brees threw for 289 yards, but lost his best receiver when Marques Colston left the game in the first half with a chest contusion that had him spitting up blood. New Orleans also lost cornerback Mike McKenzie, who departed with a sprained right knee.

EAGLES safety Brian Dawkins left the game with what team officials termed a right foot injury. He's scheduled for an MRI exam on Monday. And linebacker Omar Gaither went out with a quad contusion.

CHIEFS quarterback Brodie Croyle was knocked out of the Chiefs' 25-20 loss to Detroit when he injured his right hand trying to make a tackle on Paris Lenon's 61-yard interception return for a TD.

"MRI came back negative; it's not broken," Chiefs coach Herm Edwards said. "We'll see where he's at going into next week. Brodie probably couldn't have went back."

LIONS OT Damien Woody (shoulder), S Gerald Alexander (right shoulder) and Kansas City OT Damion McIntosh (ankle) also were injured.