Ron Rolston, coach of the Rochester Americans, Buffalo's American Hockey League affiliate, will serve as interim coach of the NHL team for the rest of the season starting with Thursday's game against Toronto, general manager Darcy Regier said.
Regier said allowing Rolston to coach the rest of the season "will provide us and him the opportunity to get to know each other, and if things go well, he'll have the opportunity to become the head coach."
The moves followed a loss to the Winnipeg Jets on Tuesday that left the Sabres with a 6-10-1 mark and at the bottom of the Northeast Division with 13 points.
Ruff, who also played most of his NHL career in Buffalo, began coaching the Sabres in 1997-98 and was the longest-tenured coach in the league.
"The hockey world knows how I and the entire Buffalo Sabres organization feel about Lindy Ruff not only as a coach but also as a person," Sabres owner Terry Pegula said.
"His long tenure with the Sabres has ended. His qualities have made this decision very difficult.
"I personally want Lindy to know that he can consider me a friend always."
Ruff, whose career ties to Buffalo spanned 25 years, had a regular-season record of 571-432-84 along with 78 ties and led the team to the 1999 Stanley Cup finals.
Winner of the Jack Adams trophy as coach of the year in 2006, Ruff was fired by general manager Regier several hours after putting the team through its paces in a practice on Wednesday morning.
Ruff, 53, the first NHL coach fired this season, was the second-longest tenured coach in North American pro sports behind only Gregg Popovich of the San Antonio Spurs (1996).