Center Sean Couturier’s spot on what had been the Flyers’ top line has been taken by Morgan Frost, who was a healthy scratch in the season’s first two games.

Frost, 21, who had seven points in 20 games last season, will be in the lineup when the Flyers play Buffalo on Monday, the first of two games against the Sabres on back-to-back nights at the Wells Fargo Center.

Couturier suffered a rib injury early in Friday’s 5-2 win over visiting Pittsburgh and is expected to miss at least two weeks.

In Sunday’s practice in Voorhees, Frost centered Oskar Lindblom and Travis Konecny, and he also was on the top power-play unit.

Coach Alain Vigneault had many options but decided he didn’t want to disrupt any of the other three lines.

“I think Morgan deserves this opportunity to play with TK and Oskar,” Vigneault said. “What went into our decision, also, was that the other lines are building some chemistry. ... Instead of shuffling everything [he made just one move]. Morgan is considered to be a skilled offensive player. I might as well put him in that role. With TK and Oskar, he’s playing with two pretty good players.”

Frost said playing NHL 20 games last year should help.

“It’s not my first game, so there’s a little less nerves,” he said. “It’s definitely been a while since I played an NHL game, so there’s still a little nerves, but I definitely feel a little more prepared than I did last summer.”

Frost, a first-round pick (27th overall) in a 2017 draft in which the Flyers selected Nolan Patrick at No. 2 overall, said he would “try to keep things a little simpler. I still want to make plays, but at the same time be reliable at both ends. Just give myself the ability to let the coaches have trust in me to keep me in the lineup, and do whatever I can to eventually stay there.”

Losing Couturier, the team’s MVP the last two seasons, “no doubt” is a gargantuan task, Vigneault said.

“He plays five-on-five against top opponents, and he plays power play, penalty killing,” he said. “But it’s next-man-up, and right now it’s Morgan, and some of the other guys are going to get the opportunity to play more minutes, whether it’s on the power play or the penalty killing.”

Frost was an AHL All-Star last season; he had 112- and 109-point seasons in the Ontario Hockey League before joining the AHL’s Phantoms.

“Frosty is a great player. His hockey IQ is very high and we’re all excited to see him back in the lineup,” captain Claude Giroux said.

Jake Voracek had been moved to the top power play after Couturier’s injury, but he slid back to the second unit in Sunday’s practice.

Entering Sunday, the Flyers were one of six NHL teams to start the season with a 2-0 record, having defeated the Penguins, 6-3 and 5-2.

Breakaways

Carter Hart (2.51 GAA, .925 save percentage) will start Monday and Brian Elliott will make his first appearance Tuesday. ... Travis Konecny leads the Flyers in goals (3), points (5), and plus-minus rating (plus-5). ... In the first two games, Vigneault noted he has sometimes been using Patrick’s line first when the Flyers had a power play, and that he doesn’t consider there to be a No. 1 or No. 2 unit. ... Center-winger Connor Bunnaman, who is on the taxi squad, practiced with the team. ... Vigneault, who said he considered moving Giroux from left wing to center, said Frost “came ready to play” from the first day of training camp and that he was confident he would step in and play well. ... Vigneault: “Five on five, we can play better. The players know this. There are a couple areas we’ve talked to our team about — working smarter when we don’t have the puck” and being better at protecting the puck.