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!"