It's the last thing anyone at Arrowhead Stadium wanted to see.

Kansas City Chiefs running back Jamaal Charles went down with a non-contact knee injury early in the second half against the Chicago Bears.

Before the injury, which occurred on a first-and-goal play from the 9-yard line with 9:33 left in the third quarter, the Chiefs were leading 17-3 and seemed to be in control.

Chiefs coach Andy Reid confirmed after the game that preliminary reports are that it's a torn ACL for the Chiefs all-time leading rusher.

After Charles left the game and was helped off the field by linebacker Justin Houston, the Chiefs had two passes fall incomplete on second and third down, which set up a 27-yard field goal attempt.

At that point, Bears linebacker Pernell McPhee, their prized free agent acquisition this past offseason, broke through and blocked the short attempt that would have given the Chiefs a 20-3 lead.

"You can't come back and have a blocked field goal in that momentum swing," Chiefs coach Andy Reid said after the game. "If it does, for that moment, then you've got to change [the momentum].

"We were never really able to do that."

The Chiefs managed just 123 yards of total offense in the second half, and 71 of those yards came on that first drive with Charles before he went down with the injury.

It was simply tough for the Chiefs to bounce back.

"[Jamaal] Charles is one of the tougher guys in the NFL," RB Charcandrick West said, "so I'm thinking he's going to get up. But to see that, it brought tears my eyes.

"It's heartbreaking to see one of my friends go down, my brother go down."

Charles had rushed the ball 12 times for 58 yards before leaving the game.

Despite the injury to Charles and even the blocked field goal, the Chiefs still had a 17-3 lead in the second half, which they ultimately weren't able to preserve as the Bears responded with 15 unanswered points in the second half.

"The second half, you got to finish off the team," Reid explained. "That's what's real. We do that and we're a pretty good football team.

"You don't do that, then you become average."

Defensively, the Chiefs made plenty of plays, but the Bears made just a few more, led by quarterback Jay Cutler.

"[Cutler] did a good job of just finding open receivers," safety Ron Parker said after the game. "He's a good, mobile quarterback. He just creates a little bit of time back there.

"He found a little extra time and he was able to hit receivers down field."

Cutler threw both of his touchdowns in the final 3:05 of the game, one to receiver Marquess Wilson and another to running back Matt Forte.

Smith said the offense didn't do enough to help the defense not be in those positions.

"Offensively, we went into a shell there for a little while," he explained. "Just didn't get anything done. Had some decent field position, really had a chance to really put that game away with some first downs and just three and out, three and out.

"It didn't help the defense at all."

It's the fourth straight loss for the Chiefs, who, not from a lack of effort, can't seem to find ways to pull out these crucial wins.

After the game, tight end Travis Kelce explained what they've been doing to try and right the ship.

"Everything you can think of man," he explained. "Everybody's staying late, [doing] extra stuff on the field, extra stuff in the offices and the classrooms.

"It's not a matter of want. It's a matter of going out there and doing it. It just rips your heart out, man."

Smith said the options from here are pretty simple.

"There are two choices," Smith explained. "You can let this get to you. You can get sidetracked, you can get distracted and you can make excuses.

"Or we all can look internally, stay together and fight."

One player who is ready to step in and fight is West, who said after the game he's ready for whatever is needed from him moving forward after the injury to Charles.

"I'm just going to step up and do my part," West said. "Whatever they call on me to do, I'm going to be there. Whatever the team needs me to do, I'm going to be ready to do that."

Reid said after the game that both West and fellow running back Knile Davis would be counted on moving forward, but Smith said it'll be up to everyone to step their game up a bit.

"It's going to be a lot of guys, not just Charcandrick (West) and Knile (Davis). It's going to be all of us as an offense.

"We're going to have to pick it up."