Ruotsalainen, 23, led the Rochester Americans with 13 points in 13 games this season. He began the year playing with Ilves of the Finnish Elite League, where he tallied a league-high 16 goals and 27 points in 19 contests before play paused due to the COVID-19 pandemic in December. He signed a three-year, entry-level contract with Buffalo in May 2019.
In a corresponding move, forward Steven Fogarty has been reassigned to the taxi squad.
Buffalo will dress 11 forwards and seven defensemen tonight. With the NHL Trade Deadline looming at 3 p.m. Monday, pending unrestricted free agent Taylor Hall will be a healthy scratch for the third game in a row.
The Sabres claimed forward Drake Caggiula off waivers this afternoon, but it's still unclear as to when he'll be able to join the club due to NHL COVID protocols. He had seven points (1+6) in 27 games with the Arizona Coyotes this season.
Faceoff between the Sabres and Capitals is set for 7 p.m. from KeyBank Center. Watch the game on MSG or listen to the action on WGR 550. Pregame coverage on MSG begins at 6:30 p.m.