GREEN BAY, Wis. -- The Packers fear tight end Tucker Kraft tore his right ACL during Sunday's 16-13 loss to the Carolina Panthers , a source told ESPN.

Kraft, the Packers' top pass catcher, suffered the injury in the third quarter and was ruled out of the game in the fourth. He is set to undergo additional testing Monday, according to Packers coach Matt LaFleur.

"It doesn't look good," LaFleur said shortly after the game. "It's going to be tough. But it's football. The other guys are going to have to step up."

Kraft appeared to injure the knee during a collision while blocking on a running play and was carted to the locker room after being examined on the sideline.

The third-year pro was coming off his best career game with seven catches for 143 yards and two touchdowns in last

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