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Jamaal Charles planted his left foot as he was being pushed out of bounds, then fell forward, crashing into the legs of Roary, Detroit's mascot.

As Charles lay on the ground with what looked like a serious left knee injury, the Kansas City Chiefs had to wonder what else could go wrong.

"I don't know the extent of his injury, but it's a terrible loss for us — for our team," teammate Thomas Jones said. "If Jamaal's gone for the year, guys have to step up."

There was no definitive word on Charles' injury after the game, but there might not be a team in the NFL in a more dire situation right now than Kansas City, which lost 48-3 to the Lions on Sunday.

The Chiefs have been outscored 89-10 in their first two games and could be without Charles for a while after he was carted off with an injury on Kansas City's first offensive drive.

"We'll probably know a lot more on him here in the next 12 hours or so," Chiefs coach Todd Haley said. "Even when he wasn't in the game, it appeared to me that we still had opportunities to make things happen, and we weren't able to do that."

Charles ran for 1,467 yards last season, finishing second in the NFL to Arian Foster and earning All-Pro honors.

He looked as if he might have hurt himself when he planted the left foot, well before he took out the legs of Detroit's mascot at the end of his fall. Charles didn't appear capable of putting any weight on the leg as he was helped onto the cart.

Kansas City (0-2) trailed 7-0 at the time and never really recovered. The Chiefs' point differential after two games is easily the worst in franchise history, according to STATS, LLC. They were at minus-27 through two games in 2007.

They turned the ball over six times Sunday and committed several crucial penalties. The Lions (2-0) drove for a touchdown on their first possession, helped by unnecessary roughness and roughing the passer penalties on Kansas City.

Detroit's Matthew Stafford threw an interception on that drive, but Jon McGraw fumbled the ball back to the Lions as he tried to return it.

"You can't do certain things and win in the NFL, or even have a chance to win. We once again did a bunch of those things," Haley said. "Once again, I will take responsibility for the performance of our team, and we have to make, clearly, a bunch of changes here in what we're doing."

In the opener against Buffalo, the Chiefs lost Pro Bowl defensive back Eric Berry to a season-ending injury — also to the left knee.

Jones actually had more carries than Charles last season and rushed for 896 yards. He had 40 of Kansas City's 151 yards rushing Sunday, but the Chiefs fell way behind and he wasn't much of a factor in the second half.

Tight end Tony Moeaki is also on injured reserve with a knee injury.

"When it's someone like Jamaal, who is basically a little brother to me, it's tough," Jones said. "He's a fighter. He's a strong-minded, determined guy. Whatever his injury is, I know he'll bounce back."

Matt Cassel was 15 of 22 for 133 yards with three interceptions for the Chiefs. Dwayne Bowe had five receptions for 101 yards.

The Chiefs kicked a field goal immediately after Charles' injury and didn't score again. They trailed 20-3 at halftime and weren't about to mount a comeback against Ndamukong Suh and the rest of the Detroit defense.

"We knew that if we could get the run stopped, that was going to be a hard game for them to play one-dimensionally," Lions coach Jim Schwartz said.

And it was easier to stop the run once Charles was out.

The Chiefs have not only dropped their first two games in ugly fashion, they also may be without an offensive standout for some time.

"The season will not be canceled as far as I know," Haley said. "What we have to do is we have to stop doing those things that are costing us dearly, and putting us in very difficult positions."

Notes: Detroit's Jason Hanson kicked two field goals in the first half, playing in his NFL-record 297th game with the same team. Hall of Famer Bruce Matthews played 296 games with the Houston-Tennessee franchise and Darrell Green was in 295 with the Washington Redskins. ... Kansas City committed eight penalties for 70 yards.