Donnie Walsh is Dr. Frankenstein, and the New York Knicks, the Pacers’ second-round opponent today at 3:30, are his monster. Or mostly his monster, anyway.

How strange is that?

The team Walsh built from the detritus left by Isiah Thomas’ bungled leadership against the team he has taken over as president of basketball operations, for however long, from Larry Bird.

“I’m proud of what the Knicks have become,” Walsh was saying, sitting courtside at the Pacers practice today at the New York Athletic Club in Manhattan. “And I’m proud of what the Pacers are, and what Larry (Bird) built here.

“I feel pride with both teams. I feel a lot of pride with seeing what New York is doing. I know at some point there I said, ‘I would love to see it get back to the way it was when the Knicks were great for the city, great for the fans.’

“The players we have (in Indiana) play hard and really want to win, and we have a great coaching staff. It’s a dreamlike thing. But it’s going to be kind of weird.”

Walsh has been back to Madison Square Garden since returning to the Pacers; it’s one of the very few trips he still makes during the regular season. But there will still be some mixed feelings as he walks through the doors of the game’s Carnegie Hall again Sunday for the reprise of the Pacers and the Knicks.

He is trying to take down the franchise he helped build back up, built back up from scratch, unloading bloated contracts in a successful effort to sign and deal for big-time players Amar’e Stoudemire and Carmelo Anthony.

The core of the Knicks are his: ’Melo, Stoudemire, point guard Raymond Felton and his draftee Iman Shumpert. The rest of the team was filled in by Glen Grunwald, the new Knicks GM and a former Indiana University player.

For so many years, Walsh built the Pacers the only way anybody could build the Pacers — through the draft and shrewd trades. He understood Indianapolis wasn’t a free agent destination, and he understood he had to maintain a successful team if the franchise was going to remain financially solvent.