PHILADELPHIA — Derrick Rose has a personal game plan for the playoffs.

It’s OK if you have to read that again, parse all its implications. It was only a week ago that everyone expected him to be traded. And the postseason? Well, that was just crazy talk.

But after a big, necessary win over the Magic on Wednesday night — spurred in part by Rose’s 19 points — the Knicks find themselves in the unexpected position of still sort of having a shot at the playoffs. And that means Rose is in the even more unexpected position of trying to find a way for the Knicks to win if they get there.

Enter the three-point shot.

“I’m trying to put pieces of my game together,” Rose said Thursday after practice at Temple University. “You see I’m not shooting threes yet, but hopefully, [I’ll] start shooting them in the playoffs. It’s going to take a lot of sacrifice and dedication to get there, but I’m just adding pieces of my game throughout the season.”

The shot is something Rose has been tweaking for some time — Jeff Hornacek said the two worked on it over the summer — but the point guard said he still isn’t comfortable using it regularly in in-game situations. Rose’s strength lies in his explosiveness while driving to the basket, and he’s more or less been happy to live there for the last few years of his career.

advertisement | advertise on newsday

He is averaging 1.1 three-pointers per game this season with a success rate of 22.8 percent, but his best year, his MVP season in 2010-11, included a more multi-faceted approach. He shot 33.2 percent from downtown and attempted 4.8 per game.

Rose has averaged 2.7 per game and shot 29.9 percent from three-point range in his career, with highs of 5.3 per game in 2014-15 and 34.0 percent in 2013-14.

“That’s where I think the pressure from point guards in this league comes [from],” Hornacek said. “Derrick can get to the basket at will, so they play behind and try to clog the lane. If he can knock down those threes, then what’s a team going to say? ‘What do we do?’ That makes it even more effective.”

“We’re kind of encouraging him to take a look at it, see it on tape, look how these guys go behind, and if you can shoot that three, [shoot it] — he shoots them pretty well in practice.”

One of the keys has been getting Rose to release the ball earlier in his jump. What they were seeing, Hornacek said, was that Rose was waiting until the very peak of his jump before letting it go. It cost a lot of energy, “and it shouldn’t look that hard,” he said. Additionally, that extra stress couldn’t have been good for Rose’s rickety, injury-prone knees.

Rose is working on a more economical shot — he releases on his way up — and he’s making progress, Hornacek said, though it likely could use another summer of work. That’s one of the reasons he is holding back for now and saving it on the off chance the Knicks can squeak into the Eastern Conference’s last playoff spot (they are four games out with 21 to play).

For now, he’s concentrating on getting a better feel for the triangle. What he recently called “random basketball” is coming more into focus, he said.

“It’s the first time I’ve played in a system ever since college,” he said. “When I first came into the league, I played for teams where every night it was a heavy dose of pick-and-roll. Coming here, I feel like I’m good enough to play in the system. It’s just learning it, getting used to it, getting familiar with it and making sure everyone is on the same page.”

Hernangomez doubtful. Willy Hernangomez (ankle) did not participate in the optional practice Thursday and likely is out for Friday night’s game against the 76ers, Hornacek said. He did not reveal if he will put Kristaps Porzingis at center, as he did Wednesday night, or start Kyle O’Quinn.