The forward was disciplined for an illegal check to the head of Bruins forward Marcus Johansson at 5:34 of the first period of St. Louis' 2-1 win in Game 5 on Thursday. No penalty was called, and Johansson remained in the game.
The Blues lead the best-of-7 series and need one win for their first Stanley Cup championship since entering the NHL in 1967-68.
Barbashev has six points (three goals, three assists) in 24 games this postseason, including one goal during the Cup Final.
He was playing on St. Louis' fourth line with center Oskar Sundqvist and forward Alexander Steen.
"Obviously, [a] very competitive guy, plays with a lot of intensity and passion," Steen said Friday. "Both sides of the puck, he's really intelligent. Good player for us."
Barbashev had an NHL career-high 26 points (14 goals, 12 assists) in 80 regular-season games.
Blues captain Alex Pietrangelo said, "He plays in all situations, right? He's been big for us on the penalty kill."
St. Louis held Boston without a power-play goal in five chances through Games 4 and 5, each a Blues win.
Forward Robby Fabbri, who played in Games 2 and 3 of the Cup Final, could be put back into the lineup. Joel Edmundson, who has played 21 games this postseason, including the first four of this series, could be used if the Blues choose to utlilize seven defensemen.
"Somebody's going to have to step in and go do the job, for sure," St. Louis coach Craig Berube said. "A lot like Sundqvist with the suspension there, somebody will come in and do the job, for sure."
Sundqvist was suspended for Game 3, a 7-2 Bruins win, after boarding Boston defenseman Matt Grzelcyk in Game 2. Grzelcyk has been in concussion protocol and has not played since.
NHL.com staff writer Tracey Myers contributed to this report
