The Bruins, 8-2-1 in their past 11 games, are second in the Atlantic Division, five points behind the first-place Tampa Bay Lightning with one game in hand, and six points ahead of the third-place Toronto Maple Leafs with two games in hand.
The Blues, 4-1-0 in their past five games after going 1-7-2 in their previous 10, are three points behind the Anaheim Ducks for the second wild card into the Stanley Cup Playoffs from the Western Conference with a game in hand.
St. Louis forward Vladimir Tarasenko, day to day with an upper-body injury, will miss his second straight game.