(John McDonnell/The Washington Post) (John McDonnell/The Washington Post)

Dating back to their time in the American Hockey League, Karl Alzner and John Carlson weren’t just a consistent defensive pairing they were joined at the hip.

Friends on and off the ice, they developed a strong chemistry as defensive partners and were one of the most stable elements over the Washington Capitals’ lineup in the previous two seasons. Rarely did they play games skating alongside anyone else and they turned into the team’s shutdown pair.

After a rough start to the season, though, they were broken up as a pairing by the fourth game. It was a move that Alzner suggested at the time, given how poorly they were playing together, and one that Coach Adam Oates encouraged, even though he knew the young blueliners weren’t keen on being separated for a long time.

“I don’t think they liked it at first but part of our philosophy was, ‘Well, what if one of you gets hurt? The other guy going to not play?’” Oates said. But in addition to broadening the skill set and familiarity of both Alzner and Carlson by playing them with other defensemen, the Capitals coaching staff wanted to create balance in the pairings.

“The point was we switch up because maybe we’re looking to make two good pairs. Maybe you complemented each other, but someone else will too,” Oates said. “That doesn’t mean that they can’t be partners. You’re always looking for chemistry, always looking for little things. Injuries play a big factor in that.”

Since they were separated, Alzner has skated primarily with Mike Green, when he’s been healthy, while Carlson has worked a lot with John Erskine and Jack Hillen. Alzner is averaging 20:58 minutes per game while providing a stable influence alongside Green, Washington’s ice-time leader (25:12) and most offensively inclined defenseman, and Carlson continues to play key minutes (23:21) against top opponents regardless who he is paired with.

Carlson downplayed the change and said it’s simply part of the job to adjust to a new defensive partner.

“We’re both good players and don’t necessarily rely on each other. We had that trust playing with each other for so long, but we’ve got six great defensemen,” Carlson said. “Whoever I play with, it’s been [Erskine and Hillen] for the majority of the year, and I think that we’ve created good chemistry and Karl is the same way.”

Alzner acknowledged that there was a transition to play with Green, but that over time they’ve developed a natural rhythm that allows them to complement each other. One of the biggest differences, Alzner explained, is Green’s preference for patience in the defensive end.

Green will handle the puck more and carry it out of the zone himself where Carlson will pressure, strip an opponent of the puck and work to manufacture a breakout quickly.

“It’s just different ways they approach the defensive play and breaking the puck out and they both work, obviously,” Alzner said. “It’s just something that takes a game or two to get used to and you play off of it.

“Me and Carly had a thing where we didn’t really need to talk a lot out there — I knew what he was going to do and he knew what I was going to do. It was similar mindsets playing together,” he added. “With me and Greenie it’s two different mindsets, but we communicate well out there so it’s easy to get that going as well. Two completely different ways of playing with a guy, but they both work out well because they’re both pros.”