The injury likely occurred while Myers was helping kill off a 5-on-3 Montreal power play late in the second period. Myers blocked two straight shots by the Canadiens' P.K. Subban right before Andrei Markov scored.
Despite the injury, Myers played a team-high 25:37.
Sabres interim coach Ron Rolston said Friday it's unlikely Myers will need surgery.
"He played the rest of the game, so it's not a major thing," he said. "It's just that he can't continue on it. It's just going to be more time than anything. He finished, he played the rest of the game, but can't move forward from there. Just get him healed up and get him strong."
Myers, the 2010 Calder Trophy winner, had eight points in 39 games. His 21:18 average ice time per game is second on the team, but his minus-8 is the worst among the team's blueliners. However, Rolston said he's been happy with Myers' play.
"I thought he was doing good," he said. "You got a couple really big blocks that gave him the injury. It was good to see him sacrificing like that."
The injury leaves the Sabres with five defensemen on the roster. Rolston said he had not discussed with general manager Darcy Regier if the team would call up a player from its American Hockey League team or use forward John Scott on defense. Scott has played defense in the NHL in previous stints with the Chicago Blackhawks and New York Rangers.