VOORHEES, N.J. — The Flyers have a massive test Sunday when they welcome the NHL-leading Avalanche.

The test could be even more massive if the Flyers don’t have Cam York, who missed a second straight practice Saturday because of an upper-body injury. The 24-year-old defenseman has been considered day to day.

The Flyers called up Ty Murchison from AHL affiliate Lehigh Valley, which likely means York won’t be available Sunday. Murchison is expected to serve as the Flyers’ extra defenseman.

The club was on the ice Thursday and Saturday, sandwiched around a day off, so that marked three straight days without a practice for York going into an early afternoon game (1 p.m. ET/NBCSP).

“Just talked to him,” Rick Tocchet said Saturday, “it’s still a day-to-day thing.”

The Flyers’ head coach called York a “slight option” for Sunday’s matchup. York suffered the injury Wednesday in the Flyers’ 5-2 win over the Sabres. He’s second on the Flyers in minutes per game with 23:31 and leads the team’s defensemen with 12 points (one goal, 11 assists).

“He’s a mobile guy, he plays all parts of the game, specialty teams,” Tocchet said. … “It’s going to be a big loss if he doesn’t play, but you guys have heard it before from everybody, it’s next man up. That’s why we play this game.”

Colorado has just two regulation losses. It’s 20-2-6 and scoring a league-high 4.00 goals per game. It’s also allowing the league’s fewest goals per game at 2.18.

Led by superstars Nathan MacKinnon and Cale Makar, the high-powered Avalanche are a team that can create all kinds of trouble for an opponent.

“We call it hunt the hash, they like to attack the middle of the ice and they like to draw you to them, and when they do, they hit the weak side,” Tocchet said. “They’re one of the best teams at hitting the weak side. That’s where we’re going to have to be very disciplined in our D-zone. We can’t chase them around because they’ll hit the weak side and that’s tough around a goalie.”

In their 15-8-3 start, the Flyers themselves have harped on penetrating the middle of the ice.

“That’s what we’re trying to do,” Tocchet said. “We’re trying to encourage players to hunt the middle and that’s when the coverage breaks down, and then you make your play from there — whether it’s a kick-out, whether it’s a shot, whether it’s a weak-side play.

“The perfect guy, you guys will see tomorrow, is MacKinnon. I never see him go down the wall, he always attacks the middle and then he makes his play from there. So we encourage that all the time and I think we’re getting better at it, I do.”

If the Flyers don’t have York, their defensive depth will be challenged.

Travis Sanheim could be in for a big day minutes-wise. Nick Seeler moved up the lineup Saturday in practice, while Egor Zamula and Noah Juulsen were together on the third pair.

Forwards

Trevor Zegras-Christian Dvorak-Travis Konecny
Nikita Grebenkin-Noah Cates-Bobby Brink
Matvei Michkov-Sean Couturier-Owen Tippett
Nicolas Deslauriers-Rodrigo Abols-Garnet Hathaway

Defensemen

Nick Seeler-Travis Sanheim
Emil Andrae-Jamie Drysdale
Egor Zamula-Noah Juulsen

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“Like Tocc says, we need everyone to be smart tomorrow,” Zamula said. “We need to be ready right away in the first 20 minutes. … We expect MacKinnon and those guys flying everywhere.”

Colorado is 12-1-0 in games decided by three or more goals, so it has really taken it to some teams. The good thing for the Flyers is that the Avalanche will be playing their third game in four days, all on the road.

Tocchet said he was excited to see how his team stacks up against Colorado.

“I don’t want us backing off, that’s the worst thing,” Tocchet said. … “You want to attack this team; you’ve just got be calculated in how you do it. That’s what we’re going to try to do.”