Nine games into his NHL career, Robert Hagg has been elevated to the Flyers' top pairing.
Based on practice Monday in Voorhees, Hagg, who has played eight games this season, will be paired with Ivan Provorov when the Flyers finish their five-game homestand Tuesday against Anaheim.
"I'm just going to try to play my game and help my 'D' partner as much as I can," said Hagg, 22, who plays with uncommon composure for a rookie.
As far as experience is concerned, Hagg and second-year pro Provorov might be the NHL's youngest No. 1 pairing.
"Hagger's a real good player and we'll try to find that chemistry as quick as possible," said Provorov, 20, who was paired with Hagg in a couple of preseason games.
Hagg was a shutdown defender, playing against teams' top scorers, with the AHL's Phantoms last season. The challenge will be tougher Tuesday against Ryan Getzlaf, Corey Perry, and the physical Ducks.
"It's going to be a fun test," Hagg said.
Andrew MacDonald's leg injury, suffered blocking a shot in Saturday's 2-1 win over Edmonton, caused Flyers coach Dave Hakstol to shuffle all three defensive pairings. The other two pairings Monday: Shayne Gostisbehere and Radko Gudas; and Brandon Manning and Travis Sanheim.
"The good thing is, the entire group is pretty versatile," Hakstol said. "The group back there will be confident and they'll be fine."
MacDonald, an alternate captain and one of the Flyers' top shot blockers, is expected to miss four to six weeks.
Captain Claude Giroux said the Flyers will miss MacDonald's leadership in the locker room, "and the way he kills penalties and [plays] five-on-five and plays against top lines most of the nights. We're going to miss him in the lineup, and it's going to be a chance for somebody to step up."
Manning will get that opportunity Tuesday after being a healthy scratch in the last two games. He will be paired with Sanheim, a rookie who had been alongside Gudas. Sanheim will shift to the right side.
"Brandon has played well and deserves to be in the lineup," said general manager Ron Hextall, who bypassed a chance to recall Samuel Morin from the Phantoms.
Manning lauded MacDonald, saying he does a "lot of subtle things" on the ice and has "done a great job with Provy, and some of that probably goes unnoticed. It's really tough to see a guy like that go down."
Hagg and Gostisbehere were a terrific duo. They are a combined plus-9.
Gudas, a stay-at-home type of defenseman, and Gostisbehere will be paired for the first time in their careers.
"We just have to feel each other out," said Gostisbehere, who entered Monday tied for the NHL scoring lead among defensemen with 11 points. "I'm sure there will be some growing pains, but hopefully our mistakes won't be magnified too much. I think it's a good fit. Obviously, Gudie is more defensive and obviously is going to kill people, and I'm a guy who is a puck mover. "
The Flyers (5-3) might recall a defenseman from the AHL's Phantoms for their upcoming two-game road trip, which starts Thursday in Ottawa. Hextall said he will make a decision after evaluating the health of his defensemen following Tuesday's game against the Ducks (3-3-1).