Montreal Canadiens head coach Claude Julien said Wednesday that team doctors haven’t definitively diagnosed forward Brendan Gallagher's condition and he will remain out of the lineup.

"(Gallagher) doesn't really have a headache right now but he's at rest," Julien said. "As you know, these things can be sometimes hard to diagnose, and all I'm gonna say is that (team doctors) don't think it has anything to do with the first concussion. But is it a bit of a setback? We don't know that. So, all we do know, as an organization and as a medical staff, is that he needs to be rested. We need to make sure that that's taken care of before we put him back into action."

Gallagher began experiencing headaches following his return to to the lineup last week after missing four games due to a concussion sustained on Dec. 31. 

The 27-year-old was without a point in 17:19 of ice time in the Canadiens' loss to the Edmonton Oilers last Thursday. He has not skated since.

Gallagher has 15 goals and 32 points in 41 games this season with the Canadiens, who have won their past two games after an eight-game winless stretch.