"He’s going to miss a significant amount of time," said head coach Travis Green. "We’ll know more in the next 24 hours. We don’t know exactly, but it’s four weeks plus. We don’t know exactly."
Tkachuk sustained the injury after taking a cross-check from Roman Josi during their 4-1 loss to the Nashville Predators on Monday.
Ottawa's leader, who has made a name for himself as one of the most physical players in the league, could still undergo surgery, but no further update has been provided as of now, other than the expected time he'll miss.
He put up three assists in three games for the 1-2-0 Senators so far this season.
Ottawa's next game is against the winless Buffalo Sabres on Wednesday, October 15th.