Blues coach Craig Berube also announced that rookie forward Robert Thomas, who is dealing with an undisclosed injury, will play Monday night against the Bruins.
Berube said Dunn is still considered day to day but that he is close to a return.
This will be Dunn’s fourth straight game missed with his injury.
He had 12 goals and 23 assists this season with a plus/minus of 14. He has two goals and five assists this postseason with a plus/minus of minus-3.
Thomas, 19, had nine goals and 24 assists during the regular season and has a goal and five assists in the postseason.