Green Bay Packers star linebacker Clay Matthews is expected to miss one month with a broken thumb, a league source told ESPN NFL Insider Adam Schefter.
Matthews, who suffered the injury in Sunday's victory over the Detroit Lions, is undergoing more testing Monday, according to the source.
Multiple sources told ESPN that Matthews likely will need to undergo surgery.
Packers coach Mike McCarthy would not disclose any information regarding Matthews' injury but said he hopes the four-time Pro Bowler will not miss the rest of the season.
"I'm hopeful it's not season-ending," McCarthy said Monday. "I think we're all hopeful, but you have to get all the opinions and make sure you always do right by the player."
Matthews was injured on the final play of the third quarter when he sacked Lions quarterback Matthew Stafford for a 12-yard loss. Matthews rushed off the edge and was unblocked on the play, which was his final snap of the game.
Team doctors took Matthews into the locker room shortly after the play. He was not in the locker room during the postgame media access.
Clay Matthews of Green Bay Packers expected to miss 1 month, source says - ESPN