Leino, who battled hip injuries on and off for four years, was finally healthy before Wednesday night's game at the Detroit Red Wings. Now he's out "at least a couple weeks," according to Rolston.
"It happened in the first period, probably about three or four shifts in," Rolston said. "It was just sore and it, obviously overnight, seized up, and he had it checked."
Leino finished the Red Wings game with 12:38 of ice time, including six third-period shifts. The Sabres will move Tyler Ennis to the wing and insert Johan Larsson at centre for Friday night's game against the Ottawa Senators.
In addition to his hip, Leino also dealt with lung problems late last season. He played in just eight games last season and a total of 80 in a Sabres uniform since signing a US$27-million, six-year contract in the summer of 2011.
The Sabres are already without three other forwards, including Corey Tropp, the forward who suffered a broken jaw in the pre-season fight with Jamie Devane that started the line brawl with the Toronto Maple Leafs.
But this is another tough break for Leino, who has just 31 points in his Sabres career.
"He had the injury bug, guys like him and Tropper you feel for," Rolston said.