Callahan, who is considered day-to-day, suffered the injury Monday night against the New Jersey Devils, but was not forced to leave the game. Newly acquired John Scott will take his place in the lineup.
Callahan has 25 goals this season, second-most on the team.
It's not just going to happen on its own. We have to have guys commit to the areas we need to improve on. We're going to be better than last year but there is still a long way to go. But I really like the pieces and where we're headed.
— Sabres forward Tyler Ennis on the progress of Buffalo's rebuilding process