While we hope roster answers are already within the organization, perhaps the Blues can find some solutions on the waiver wire.
At the start of every NHL season, teams must pare down their preseason training camp rosters to 23 players--enough players to field a 20-man team on a nightly basis with a few extras to rotate in if necessary. Things will be no different for the St. Louis Blues, as they'll have to send a mix of young players on bridge deals, AHL veterans, and other players who've been beaten out for a roster spot.