Allen missed the start of training camp with back spasms but has been practicing with the team since Sept. 18.
"Things are looking up. I'm glad to be in a game," Allen said. "It feels like camp has gone on forever, to be honest, because I wasn't really part of it at the start... Not being able to play the last couple games, I'm looking forward to (playing). It should be fun."
Allen is expected to play the first two periods of Tuesday's game. Chad Johnson will play in the third period.
Blues Head Coach Mike Yeo said he doesn't have a plan for the goalies past Tuesday's game, but that he anticipates getting Allen as much playing time as he can in the remaining exhibition games.