Lalime left the Senators’ 2-2 tie with Toronto on Saturday six minutes into the first period after spraining his left knee. Martin Prusek replaced him after Lalime tripped into his own net.
“I just caught it and fell on it,” said Lalime, who was limping badly. “It’s day to day. I’ll know more tomorrow.”
Rob Ray and Chris Phillips scored for the Senators, who are competing with Toronto for home-ice advantage in the playoffs. Ottawa is one point behind Northeast Division-rival Toronto for fourth place in the East.
Boston leads the Northeast, two points ahead of the Maple Leafs.
Ottawa is trying for a season series sweep of Eastern Conference-leading Tampa Bay. The Senators have outscored the Lightning 12-5 in three wins.
The Lightning took another step toward clinching home-ice advantage in the playoffs Saturday, beating the Washington Capitals 4-1.
Vincent Lecavalier scored two goals for Tampa Bay, which leads the Boston Bruins by four points for the top seed in the conference, and is tied with the Detroit Red Wings for the overall NHL lead with 103 points.
“We just want to stay away from bad habits and continue to play,” Lightning coach John Tortorella said. “Continue to work on our game.”
Lecavalier has 32 goals, one short of his career high set last season.
“I feel confident, and obviously the more goals you score, the more you feel good,” Lecavalier said.
Richards moved into first place on the Tampa Bay career assist list with 190 by assisting on Modin’s goal.
Lightning defenseman Darryl Sydor sat out for the second straight game with an upper body injury. His status for Monday’s game is uncertain.