No one who has watched the Islanders over the past decade, or perhaps even longer, needed Pete DeBoer to remind them what the power play has looked like for the vast majority of that period.

Nevertheless, it was good to hear a stark acknowledgement of reality Saturday when the Islanders started work on the power play for the first time during camp.

“It’s not a quick fix,” DeBoer said. “It hasn’t been good for quite a while.”

Indeed, for a team that counted 16.53 percent and 30th overall on the power play as an improvement, tearing the thing down to the studs is entirely warranted.

DeBoer and Rocky Thompson, the assistant coach in charge of the power play, have their hands full.

Matthew Schaeffer, looking on during a recent practice, is set to be a member of the Islanders’ first power-play unit. Corey Sipkin for New York Post

The first vestiges of their work on Saturday revealed two things.

First, the composition of the units: Matthew Schaefer up top, Bo Horvat in the bumper, Brayden Schenn netfront, Cal Ritchie and Kyle Palmieri on either flank as PP1; Tony DeAngelo up top, Anthony Duclair in the bumper, Emil Heineman netfront, Mattias Maccelli and Simon Holmstrom on the flanks as PP2.

Second, movement of players is being stressed as much as movement of the puck.

“The good power plays are interchangeable,” DeBoer said. “There’s a lot of motion, there’s a lot of movement. There’s a lot of guys moving to different parts of the ice and they’re interchangeable in their positioning. I felt like this group was really stagnant, almost deferring to, well that’s my spot there, that’s your spot.”

That might be a good first step to recovery.

“Guys are so good at reading plays now, you have to be more unpredictable,” Bo Horvat told The Post. “I think us being a little more fluid and not standing around so much is gonna help for sure.”

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Matthew Schaefer was on the right Saturday, the first time this camp in which he’s practiced on his off side, skating on a pair with Adam Pelech.

DeBoer said the ultimate decision on which side Schaefer plays will come down to how the rest of the defense corps sorts out, with the competition ongoing between Isaiah George and Scott Mayfield, with Kashawn Aitcheson, Marshall Warren and Matt Kessel in the mix as well.

George, who formed a pair with Mayfield on Saturday, is a lefty whose presence in the lineup would likely require someone — Schaefer — to play their off side.

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The Islanders split into NHL and AHL groups Saturday, with DeBoer only on ice with the NHLers.

Victor Eklund and Aitcheson were both included in the NHL group, with Eklund continuing to skate on a line with JG Pageau and Emil Heineman. Cole Eiserman was with the AHLers.