BOSTON -- After a two-year absence, the Boston Bruins are back in the playoffs.

Tuukka Rask continued his late-season surge, making 28 saves for his second shutout in four starts in leading Boston to its sixth straight win, a 4-0 victory over the Tampa Bay Lightning that clinched the playoff berth with two games remaining.

All that is left for the Bruins is to determine whether they will be second or third in the Atlantic Division or in the second wild card spot. Boston (44-30-6) hosts the Ottawa Senators on Thursday and the Washington Capitals -- both potential first-round opponents -- Saturday.

But the victory could have been costly for Boston. Brad Marchand was ejected in the first period for spearing Jake Dotchin in the groin. Marchand, a 39-goal scorer, received a major penalty and game misconduct and faces league discipline that could result in his seventh suspension. He was fined the maximum $10,000 for an incident, also involving the Lightning, earlier this season.

The loss put the short-handed Lightning (39-30-10) on the brink of playoff elimination as they saw a five-game road winning streak stopped and suffered their first regulation loss in their last seven games overall.

The six-game winning streak is Boston's longest since a 12-gamer in 2014.

Rask, who pitched his eighth shutout of the season and the 38th of his career, won his fourth straight since being called out by interim coach Bruce Cassidy for his play in Tampa Bay's 6-3 victory at TD Garden on March 23. He allowed three goals in the four games.

David Pastrnak scored his 33rd and 34th goals of the season, Drew Stafford netted his first in 12 games and Zdeno Chara scored a power-play goal. David Krejci had two assists.

Boston, 18-7-0 under Cassidy, dominated in the faceoff circle, with Patrice Bergeron winning all 17 of his draws.

Dotchin, in obvious pain, was able to return in the second period, important because his team was already playing a man short from the start of the game.

Tampa Bay goalie Andrei Vasilievskiy played well, making 34 saves. Pastrnak's second goal went into an empty net.

NOTES: Tampa Bay C Steven Stamkos still wasn't quite ready to return from the knee injury that caused him his 62nd straight game, but he would not rule out playing again this week. "As long as we're still in the mix, I consider it worth it," he said. "We're in the mix, a big one tonight. We'll see." ... D Jason Garrison, who returned Sunday after missing four games with a lower-body injury but played only two periods, was a scratch for the Lightning as was C Gabriel Dumont, whose wife was giving birth. His sudden departure left his team a player short in the game -- the second time in four games that has happened. D Luke Witkowski moved to forward. ... The Bruins, who signed F Jakob Forsbacka-Karlsson out of Boston University on Sunday, were still waiting for immigration paperwork before he could report. ... Tuesday night was Brad Marchand Bobblehead Night.