After sitting out Thursday against Ottawa, Trent Frederic returned to the lineup and scored on his first shift against Pittsburgh.

Linus Ullmark left Thursday’s game with an apparent concussion, leaving Jeremy Swayman as Boston’s No. 1 goalie for now.

Boston gets early goals from Trent Frederic and Erik Haula, and Jeremy Swayman makes 23 saves in a 2-1 win over Pittsburgh.

Boston has now dropped three straight games for the first time this season, plus goalie Linus Ullmark leaves with an undisclosed injury.

Boston has lost 3 of 4 games and Coach Bruce Cassidy needs the Bruins to refocus with the playoffs on the immediate horizon.

The Bruins, playing without three starters, lost defenseman Brandon Carlo to an injury early in the first period.

Matt Grzelcyk plays just four shifts in a loss to Washington with an apparent injury.

Linus Ulmark makes 27 saves, but banged-up Boston has its two-game winning streak snapped.

Boston moves into sole possession of third place in the Atlantic Division.

Detroit goalie Alex Nedeljkovic makes a season-high 47 saves and adds an assist.