The Avalanche’s trip to St. Louis on Saturday for a division game against the Blues will not include Paul Stastny. He left Colorado after last season as a free agent.

But he will also not play for St. Louis. Stastny was ruled out for Saturday’s game by Blues coach Ken Hitchcock because of a shoulder injury, according to the St. Louis Post-Dispatch.

If Stastny’s injury ruins the narrative, it won’t bother Avalanche coach Patrick Roy. His team earned just its third victory Thursday night, a 5-0 rout of the New York Islanders in Colorado.

“It’s an important stretch,” Roy said of the Avs’ trip to St. Louis, followed by three home games in five games next week.

“We’ve talked about it. The Blues are playing really well right now. It’ll be a good test for our team. It’s a division game for us against the Blues.”

The Avs broke out for five goals against the Isles behind two from second-year forward Nathan MacKinnon and 40 saves from goalie Semyon Varlamov. But Colorado (3-4-4) remains in sixth place in the seven-team Central Division, trailing St. Louis (5-3-1) by one point.

“We’ve got something going on,” Roy said. “We’ve picked up points in our last five games. We just need to continue on with that.”

The Blues, too, are on a roll with three consecutive victories.

“This is a league where, if you get on a little bit of a roll, you just run until you run out of gas,” St. Louis coach Ken Hitchcock told reporters Thursday night after a 2-0 win over the Los Angeles Kings. “We’ve won three in a row. We have to run until we run out of gas.”

Stastny left a game against Arizona last week with his left arm in a sling after he took a hard hit from Coyotes forward Martin Hansal. Stastny was listed as day-to-day, but he’s now on the Blues’ injured reserve list.

A star center for the Avs over eight years, Stastny was the Blues’ biggest offseason signing. He started this season with a goal and three assists.

Stastny won’t be the only Blues player out. Center Joakim Lindstrom remains questionable with an infection after sickness spread through the St. Louis locker room in recent days. Winger T.J. Oshie, a U.S. Olympic hockey team member, will miss the game with concussion symptoms. His U.S. teammate, St. Louis captain David Backes, is also questionable, but unlikely, after a concussion.

“You just have to roll with the punches,” St. Louis general manager Doug Armstrong told the Post-Dispatch on Thursday night.

“You come in and if the trainer says they can play, they go in the lineup. If not, you adjust to it. There’s not a lot of reason to waste energy on it because you can’t change the result. The good teams overcome it and that’s what we have to find out — if we can do that. “

The Avs, meanwhile, remain relatively healthy, with only center Jesse Winchester (concussion) on injured reserve.

Roy decided the Avs would not skate a practice session Friday before leaving for St. Louis. The Avs also didn’t skate Wednesday, one day before their blowout win over the Isles.

Nick Groke: ngroke@denverpost.com or twitter.com/nickgroke