Demers was injured Tuesday in the Stars’ game against the Montreal Canadiens when he got tangled up with Lucas Lessio.
“We will know in about six weeks where he is. We will have an update after that,” Ruff said.
“Probably Sharp is doing the best out of all of them. Klingberg looks like he is still a period of time away. Jordie Benn still a little bit of time away,” Ruff said. “I don’t think there is an exact day for them."
The Stars sit tied for first in the Central Division with the Chicago Blackhawks.