CHICAGO (AP) — Blackhawks defenseman Duncan Keith will be sidelined for four to six weeks after he had right knee surgery on Tuesday.

Keith, a two-time Norris Trophy winner, has two assists in six games this season. The team says he had a meniscal tear repaired.

The loss of Keith, who won the Conn Smythe Trophy last season for playoff MVP, is a huge blow for the Stanley Cup champions. They play in one of the NHL's toughest divisions, and every point could make a difference at the end of the year.

Keith is likely headed for long-term injured reserve, giving the Blackhawks some cap relief. Lubomir Visnovsky, a veteran defenseman who was with the team during training camp, could be brought back, or they could promote someone from the minors.