COLUMBUS - Forward Marian Gaborik will likely miss at least four weeks with a sprained knee, Columbus Blue Jackets coach Todd Richards said Friday.

"It's a big hole," Richards told the media a few hours before the Blue Jackets' game against the Montreal Canadiens at Nationwide Arena. "But now we're looking for somebody to step up and fill that hole. … There are going to be opportunities there for somebody."

Richards' immediate plan is to insert Sean Collins in the lineup. But Collins is normally a fourth-liner while Gaborik, 31, is always on the one of the top two units. He had been playing on the second line with R.J. Umberger and Artem Anisimov.

Mike Foligno or Michael Chaput could assume Gaborik's spot. The top line of Brandon Dubinsky, Ryan Johansen and Cam Atkinson is expected to remain intact.

Gaborik has five goals and 11 points in 17 games to rank third in team scoring while averaging 17:36 of ice time. He's also been a regular on the power play.

The three-time 40-goal scorer has gone eight games without a goal since scoring against the Toronto Maple Leafs on Oct. 25. He has no points in the past three games.

Columbus received some good news as offseason free-agent signee Nathan Horton continued rehabbing from left shoulder surgery in July. He hopes to return before the end of December and has been shooting pucks this week for the first time since the procedure.

"I'm shooting but I'm not really pressing it because I still have some soreness," he said Friday.

Horton will travel with the team on its five-game swing through Canada that begins Saturday at Ottawa to continue his conditioning.