Source: Eric Berry out for season

KANSAS CITY, Mo. -- The bad news in Kansas City just got worse.

Pro Bowl safety Eric Berry will miss the remainder of the Chiefs' season after tearing the ACL in his left knee, a source told ESPN NFL Insider Adam Schefter.

The NFL Network first reported news of Berry's season-ending injury.

Berry was hurt during the first quarter of Sunday's blowout loss to Buffalo on a block by Bills wide receiver Steve Johnson, a person familiar with the injury told The Associated Press on Monday. The block occurred on the third offensive play of the game.

Berry was helped to the sideline then tried to return on the Chiefs' next defensive series. He went down on the first play and did not get up until trainers came out on the field to check on him.

"I won't go into details, but I will say it appears he will be out for the season," Chiefs coach Todd Haley said Monday. "I know we just lost one of our best players and that hurts."

The 41-7 loss was ugly enough, but losing Berry was just the latest blow on the injury front.

The Chiefs lost tight end Tony Moeaki to a season-ending left ACL injury in their final preseason game. Linebacker Brandon Siler was lost during training camp to a torn Achilles, and wide receiver Jon Baldwin -- their first-round draft pick -- hasn't been a full participant in practice since early in camp after hurting his right thumb during an altercation with a teammate.

"I've said it many times, injuries happen," Haley said. "People are going to go down. I'm sure across the league, a number of guys were probably lost for the season yesterday."

Haley wouldn't say whether he thought the hit by Johnson was dirty, even though it appeared the Bills wide receiver deliberately dived for Berry's knee. There is nothing in the NFL rule book that prohibits blocks below the waist in the open field unless they happen from behind.

Johnson was not available at Bills practice, but he did respond to a fan's tweet that called the block a cheap shot: "Man shutup u clown," Johnson said. "ILL NEVER CHEAPSHOT A PLAYER ON THE FIELD! IDC if he my Enemy U Square! Last I checked a cut block was legal!"

Bills coach Chan Gailey also defended the block.

"We tell our guys, 'Hey, you go block those guys because let me tell you, if you're up in the air, they're not going to hesitate to go get you and to take a shot at you,' " Gailey said. "That's an opportunity for our receivers to go down the field and hit those guys. It's legal."

Gailey pointed out the block happened about 10 yards from an official.

"It wasn't the only person we went down and cut," he said. "It wasn't the only time we did it."

Berry, the fifth overall pick in the 2010 draft, was being counted on heavily by the defending AFC West champions.

The former Tennessee star made 72 tackles and four interceptions last season, returning one of them for a touchdown, and wound up going to the Pro Bowl. His enthusiasm quickly endeared him to Chiefs fans, and his teammates voted him one of the captains before the season.

"That's one of those that really digs you deep, you know, first and foremost, just from the standpoint I know how hard he's worked, how much it means to him," Haley said. "It's devastating for him, so that's the biggest heartache for me."

Haley refused to discuss how Jon McGraw and Sabby Piscitelli performed in Berry's absence, even though both of the backup safeties struggled mightily against Buffalo.

Career backup Ryan Fitzpatrick threw for 208 yards and four touchdowns, two of them to journeyman tight end Scott Chandler. On one of those catches, Chandler came off the line and was never picked up by a linebacker or safety, and Fitzpatrick took advantage of the confusion by simply floating a pass to Chandler standing all alone in the end zone.

The overall performance by Kansas City was so bleak that Haley gathered the entire team at its practice facility on Monday to review film. Haley said he does that occasionally when there's been a particularly bad practice or game, and Sunday certainly fit that description.

"I'm more concerned with us," Haley said. "The whole entire team, we know now the areas that we have to make improvements, and we knew it yesterday when it was occurring, because it was pretty obvious stuff. It was a team loss that I take full responsibility for, and I say I'm very encouraged by how today went, that our team and our group of guys will not let it linger."

Information from The Associated Press contributed to this report.