BOSTON -- The Boston Bruins lost their most important game of the 2015-16 season Saturday without No. 1 goalie Tuukka Rask, who was sidelined with an illness.

Without Rask, backup Jonas Gustavsson allowed four goals in the second period of a 6-1 home loss to the Ottawa Senators in the regular-season finale.

The loss left Boston tied with Detroit with 93 points and trailing the Red Wings in the tiebreaker.

"When you look at what's happening this afternoon, it's even more disappointing because we could have controlled our own fate," Bruins coach Claude Julien said. "Right now, all we can do is cross our fingers and hope for a miracle."

That miracle was officially dashed later Saturday afternoon. The Bruins were left out of the playoffs after the Philadelphia Flyers beat the Penguins to clinch the No. 8 seed.

Gustavsson led the Bruins out for pregame warm-ups, during which Rask was on the ice. However, with the exception of a few shots, Rask did not participate. He stood leaning on the boards in front of the bench.

Prior to the game, the team recalled goalie Jeremy Smith from Providence of the AHL on an emergency basis. Before Saturday, Gustavsson was 11-8-1 with a 2.65 goals-against average and a .910 save percentage in 23 games this season for the Bruins. He is 4-3-0 with a 2.05 GAA and a .930 SP in eight career games against the Senators.

The Associated Press contributed to this report.