Matthews underwent successful surgery on the thumb Monday night, according to Fox Sports' Jay Glazer.
"I'm hopeful it's not season-ending," Packers head coach Mike McCarthy said. "I think we're all hopeful, but you have to get all the opinions and make sure you always do right by the player."
The Packers still can place one player on their injured reserve/designated-for-return list. Such a move would provide flexibility to sign another player to take Matthews' roster spot, but Matthews would have to sit for at least six weeks.
Matthews has 18 tackles, three sacks and two forced fumbles this season.
Clay Matthews had successful surgery on his thumb today.SI WIRE: Lions center accused of harassing college band
— Jay Glazer (@JayGlazer) October 8, 2013