Coach Lindy Ruff said before the game that Sekera will miss at least a few days and potentially longer.
Sekera was hurt Saturday, when he was struck in the leg by Canadiens defenceman Alexei Emelin's shot in the first period of a 6-1 loss at Montreal. He played a few more shifts before missing the final two periods.
The Sabres are already missing veteran defenceman Robyn Regehr (lower body), who will miss his fourth straight game. Ruff said Regehr is expected to return to practice this week.