"Thomas has got the flu pretty bad," Sabres coach Lindy Ruff told the Buffalo News after Tuesday's morning skate. "He hasn't left the hotel yet. No chance."
Vanek is leading the team with 55 points (23 goals, 32 assists) in 65 games.
Buffalo is trying to hold onto the eighth and final playoff spot in the Eastern Conference with just a one-point advantage over ninth-place Carolina.