Thomas did not practice with the team on Monday at Centene Community Ice Center. He played 20 minutes and 15 seconds in Saturday's 4-3 shootout loss in Florida.
Thomas (day-to-day) joins a list of injured players that includes David Perron, Klim Kostin and James Neal. The team is also without Jordan Binnington, Justin Faulk and Tyler Bozak due to COVID-19 protocols.
Vladimir Tarasenko also didn't skate Monday, but Berube labeled his absence as simply a maintenance day.
With Thomas out, the Blues are down to just 17 skaters.
"Forwards are going to get a lot of ice time, that's the bottom line," Berube said of playing shorthanded. "You've got to play smart. You can't force things, you have to have real good line changes, keep your shifts short. Discipline, staying out of the penalty box, we don't need to be killing a lot of penalties. Then go out and play, compete hard and work hard. And (then) you give yourself a chance."
The Blues will begin a four-game homestand on Tuesday that includes matchups with the Florida Panthers, Detroit Red Wings, Montreal Canadiens and Anaheim Ducks.