Winnipeg forward Mark Scheifele did not play in Game 7 of the Jets’ first-round Stanley Cup playoff series against the St. Louis Blues on Sunday due to an undisclosed injury, coach Scott Arniel said.

Arniel ruled out Scheifele following the team’s morning skate. He was hurt in Game 5 — playing only 8:05 in the first period before exiting — and then did not travel with the Jets to St. Louis for Game 6. Arniel previously had said Scheifele was a game-time decision for Game 7.

Scheifele, 32, skated in a track suit Saturday, and Arniel told reporters the veteran was feeling better than he had the day before. Scheifele, however, was not able to participate in the Jets’ on-ice session by Sunday, quickly indicating he would not be available for the game.

Winnipeg held a 2-0 lead in the series over St. Louis before the Blues stormed back with a pair of wins to tie it, 2-2. The home team has won each game in the best-of-seven series so far.

The Jets’ challenge in closing out St. Louis only increases without Scheifele. Winnipeg already has been dealing with the uneven play of goaltender Connor Hellebuyck, a significant storyline in the series to date. Hellebuyck was pulled in all three of his starts at St. Louis while giving up a combined 16 goals on 66 shots (.758 SV%). In Game 6, Hellebuyck allowed four goals in only 5 minutes, 23 seconds of the second period.

Hellebuyck was Winnipeg’s backbone during the regular season, earning a Hart Trophy and Vezina Trophy nomination for his impeccable year (.925 SV%, 2.00 GAA).

Stars coach Pete DeBoer expects to have leading goal scorer Jason Robertson and standout defenseman Miro Heiskanen available in the Western Conference semifinals after both missed Dallas’ first-round series win over the Colorado Avalanche.

Following their thrilling Game 7 comeback victory over the Avalanche on Saturday night, the Stars await the winner of Sunday night’s Game 7 between the Winnipeg Jets and St. Louis Blues. If the Blues win, the Stars will have home-ice advantage in the best-of-seven series.

“I believe you’re going to see them both play in the second round, but I don’t know if it’s going to be Game 1 or Game 3 or Game 5,” DeBoer said after Saturday’s series clincher. “I consider them both day-to-day now, but there’s still some hurdles. It depends on when we start the series, how much time we have between now and Game 1. We’ll have a little better idea as we get closer.”

Robertson, 25, who posted 80 points (35 goals, 45 assists) in 82 games this season, suffered a lower-body injury in the regular-season finale April 16 and was considered week-to-week at the time.

Heiskanen hasn’t played since injuring his left knee in a Jan. 28 collision with Vegas Golden Knights forward Mark Stone. Initially expected to miss three to four months, the 25-year-old defenseman had surgery Feb. 4 and sat out the final 32 games of the regular season. In 50 games, he collected 25 points (five goals, 20 assists) and averaged 25:10 of ice time, which ranked fifth among NHL blueliners.

BOSTON — Boston Red Sox first baseman Triston Casas suffered a ruptured tendon in his left knee and is out for the remainder of the season, the team said.

The 25-year-old Casas ruptured his patellar tendon running to first on a slow roller up the line and fell awkwardly in Boston’s victory over the Minnesota Twins on Friday night. After laying on his back in pain — not moving the knee — he was carted off on a stretcher before being taken to a Boston hospital.

The team announced Sunday that he had surgery for a left patellar tendon repair at Massachusetts General Hospital. The surgery was performed by Dr. Eric Berkson.

“I talked to him last night,” chief baseball officer Craig Breslow said in a news conference on Saturday discussing the injury outside Boston’s clubhouse. “We exchanged text messages [Saturday]. We all care deeply about just his overall wellbeing.”

Manager Alex Cora said Casas worked hard during the offseason to play every day after missing a large amount of last year with torn cartilage in his rib cage.

“He did an outstanding job in the offseason to put himself in that situation. It didn’t start the way he wanted it to,” Cora said of Casas’ struggles. “He was going to play and play a lot. Now we’ve got to focus on the rehab after the surgery and hopefully get him back stronger than ever and ready to go next year.”

Casas batted just .182 with three homers and 11 RBIs, but Breslow said his loss will be felt, especially with the team’s lack of depth at the position.

“He certainly struggled through the first month of the season but that didn’t change what we believe his production was capable of being,” Breslow said. “It’s a big loss. In addition to what we think we were going to get on the offensive side, he was kind of like a stabilizing presence on the defensive side of the field — also a big personality and a big part of the clubhouse.”

During spring training, Casas talked about how his focus at the plate this season was being more relaxed.

“You really want it until you don’t,” he said, explaining his thoughts while standing at his locker. “Then you can’t want it that much.”

Now, he’ll have to focus on his recovery plan for next season.

Casas, a left-handed batter, was placed on the 10-day injured list Saturday with infielder/outfielder Abraham Toro selected from Triple-A Worcester.

Cora said Toro — a switch-hitter — will split time at first along with Romy Gonzalez. who bats right-handed.

Breslow said the team might be exploring a long-term replacement.

“This is unfortunately an opportunity to explore what’s available,” he said. “We’ll look both internally and outside as well.”

Cora said there are no plans to move Rafael Devers, who was replaced at third by offseason free-agent acquisition Alex Bregman and moved to DH.

“We asked him to do something in spring training that in the beginning he didn’t agree with it and now he’s very comfortable doing what he’s doing,” Cora said. “Like I told you guys in spring training, he’s my DH.”