KANSAS CITY, Mo. (AP) Pro Bowl running back Jamaal Charles could miss the rest of the season with a serious knee injury sustained in the third quarter of Sunday's 18-17 loss to the Chicago Bears.

Charles had taken a carry deep in Bears territory when he tried to cut left, his right knee buckling at a gruesome angle. He immediately went to the locker room, and Chiefs coach Andy Reid said after the game the preliminary diagnosis was a torn ACL.

Charles will have an MRI on Monday to confirm the extent of the injury.

''We'll just see how that goes,'' Reid said.

Charles missed most of the 2012 season after tearing the ACL in his left knee. In that case, he stepped awkwardly out of bounds while finishing off a carry in a game in Detroit.

The injury Sunday seemed to deflate the Chiefs, who led 17-3 at that point.

Their drive stalled after Charles was helped to the sideline, and Kansas City had to try a 26-yard field goal that was blocked by Pernell McPhee. The Bears suddenly seized the momentum, getting a field goal later in the third quarter to jumpstart their comeback.

Jay Cutler led two scoring drives late in the fourth quarter, hitting Matt Forte with the go-ahead touchdown pass with 18 seconds remaining for the victory.

''It hurts. We felt like we played way better than what the loss shows,'' said Chiefs kicker Cairo Santos, whose 66-yard field-goal attempt as time expired was well short.

Reid said the Chiefs were fairly certain that Charles had torn ligaments in his knee when he was helped off the field. At that point, he had carried 12 times for 58 yards.

''People saw what was going on. They had a pretty good idea,'' Reid said. ''I think it was more of a non-contact type of thing. But again, those types of things, you can't come back and have the blocked field goal and have the momentum swing.''

Charles had been off to a relatively slow start this season, getting just 11 carries each of the past two weeks. He also had two fumbles in a loss to Denver, including one returned by the Broncos in the final minute for the decisive touchdown in a 31-24 victory.

But the Chiefs also have no bigger playmaker than Charles, who's run for at least 1,000 yards each of the past three seasons. He had 12 touchdowns rushing a couple of years ago, nine last season, and had already reached the end zone four times this season.

Without him in the lineup, the Chiefs will be forced to lean on third-year player Knile Davis and Charcandrick West, a former undrafted free agent out of Abilene Christian.

''Jamaal is one of the heartbeats of this team,'' wide receiver Chris Conley said. ''People here love him. We love him in this locker room. To not have him on the football field, it hurts us. It hurts us scheme-wise and it also hurts us because we feel for him.''


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