Logan Brown did not practice Monday and is day to day with an upper-body injury.
The forward sustained the injury in a 5-2 loss to the Dallas Stars on Saturday in Independence, Missouri.
Brown leads the Blues with five points (four goals, one assist) in three preseason games.
"He should be fine," coach Craig Berube said. "Day-to-day kind of thing. Hopefully it's not too long and he can get in a game here again."
Forward Vladimir Tarasenko also missed practice Monday because of an illness.
Zachary Bolduc, the No. 17 pick in the 2021 NHL Draft, was assigned to the Quebec Ramparts of the Quebec Major Junior Hockey League on Sunday.
The 19-year-old forward did not have a point in three preseason games.
"He's a kid, he's going to go back to junior, he's not ready yet for this level," Berube said. "He's got to go down and play with more pace in his game. I think he has the ability with his feet to do a lot more than he does with the puck. He's got to skate more, make more plays and not just be a shooter. He's capable of doing more with his ability.
"Defensively, he's got to improve. He's got to be more responsible defensively, understand the responsibilities of playing good D and checking. In the games he played, I think he realizes how quick it is and we're not even in the regular season yet." -- Lou Korac