Second-year Chiefs safety Eric Berry will miss the rest of the season after hurting his left knee in Sunday's season opener against Buffalo.
The injury was reported to be a torn ACL, which knocked Berry out in the first quarter of Kansas City's 41-7 loss.
"I wont go into details, but I will say it appears he's going down for the season," head coach Todd Haley said Monday.
The loss of Berry, who the Chiefs picked No. 5 overall in the 2010 NFL Draft, was a blow so early in the season.
"Eric is a special, and will continue to be a special player," Haley said. "That's one of those (injuries) that really digs you deep, first and foremost from a standpoint of I know how hard he works."
Haley said every player will have to elevate their game "to counterbalance that loss."
"I just know we lost one of our best players and that hurts," he said.
Berry started all 16 games in his first NFL season and collected 92 tackles and four interceptions, returning one 54 yards for a touchdown. The contract he signed in July 2010 was reported to be for six years and $60 million, with $34 million guaranteed.