It's the third time the Sabres' 2009 first-round draft pick has been called up this season. Saturday's move comes a day after forward Cody McCormick was hurt in a 3-2 shootout win over Dallas.
Kassian has three goals and three assists in 19 games with Buffalo this season.
The Sabres also loaned rookie center Luke Adam and rookie defenseman T.J. Brennan to Rochester.
Adam is tied for eighth among NHL rookies with 20 points (10 goals, 10 assists), but has been in an extended slump with no points in his past 20 games. Brennan has been cleared after missing seven games with an upper body injury.
Buffalo hosted Tampa Bay on Saturday night.