The 21-year-old Lapierre found himself skating with the two struggling veterans in practice on Wednesday. The first test comes Thursday night against the foundering Flyers in Philadelphia.
"I have a simple game to play - I go in the corner, get the puck and drive the net. I think they'll like it," said the six-foot-two 195-pound Lapierre, a second-round draft pick in 2003.
But it is Kovalev who calls the shots on that trio.
"I need him to go to the net, not in the corners," Kovalev pronounced. "I'll play in the corners.
"I wouldn't mind seeing him score more goals than I do, so I'll set up the play."
It's all part of a round of line-juggling by Carbonneau, done in part because centre Radek Bonk is sidelined by a neck injury, and also to get more even-strength goals from a team that relies too much on its special teams.
Rookie Guillaume Latendresse has found himself on the top line with Saku Koivu and Michael Ryder while, in Bonk's absence, Chris Higgins is shoring up the checking line with Mike Johnson and centre Tomas Plekanec.
Alexander Perezhogin was moved to the fourth line, likely with Mark Streit and either Garth Murray or Aaron Downey.
After a solid showing with Hamilton in the AHL this season, Lapierre had three goals and an assist in a four-game call-up to the Canadiens in December.
He was recalled again on the weekend with centre Mikhail Grabovski while the NHL team was reeling from a gastro-intestinal virus. This time, he is without a point in three games.
Grabovski, who was electric at times on attack but not so much on defence, was returned to Hamilton on Wednesday when Murray came off the injured reserve after suffering a hand injury.
Goals have been few for Samsonov and Kovalev this season, mostly with Plekanec at centre, but Carbonneau has chosen a bigger, more physical player in Lapierre to try to get them going.
"Maybe he's the guy," said Carbonneau. "He'll go in the corners and get the puck and go to the net. Maybe that's what that line needs now."
It needs something.
Samsonov, the team's main off-season signing, has only six goals and Kovalev, the Habs' big gun on attack, has just 10.
"It's no secret our line's been struggling," said Samsonov, a two-time 29-goal scorer who has just two goals in his past 33 games, and zero in his last 13. "Max is a fast skater, so hopefully he can add a dimension to our line.
"He plays that north-south game where he goes in the corners and gets some hits and when he gets the puck, he skates like the wind. Hopefully we can find some chemistry."
Kovalev reserved judgment until they've played a game together, but he likes what he's seen of Lapierre.
"He's proven he should be here, but you can't predict anything," he said. "We just hope our line starts clicking and we start scoring some goals.
"He has a lot of speed, he likes to go to the net and score, so that's important."
Plekanec has been playing less with Samsonov and Kovalev of late and suddenly has started scoring. The 24-year-old has four goals and an assist in his last four games.
However, he cautioned against drawing the conclusion that his former linemates were dragging him down.
"The puck's just going in for me," he said. "Before, I'd get a great pass from Alex and it didn't go in.
"Now it's going in, that's all."
The Canadiens can use all the scoring they can get.
A 4-2 win over Atlanta on Tuesday night ended a three-game losing streak and a three-game run without an even-strength goal.
In Philadelphia, they face the NHL's last-place team and worst defensive club with 165 goals allowed. The Flyers, who will play their first home game after an eight-game road trip, have dropped four in a row and 13 of their last 16 games.
Then the schedule gets tougher for Montreal, which plays in Ottawa on Saturday and in Detroit on Monday night.