NHL

RANGERS TRADE FULL OF MYSTERY

In surrendering the second-round pick to Toronto that all but surely will fall between 44th and 52nd overall in June’s entry draft in exchange for impending free agent Nik Antropov, it’s possible the Blueshirts might have traded the next Shea Weber (49th overall by Nashville in 2003) for a mid-level rental.

But if past is prelude, and given that Daniel Goneau (48th in 1996) has been the Rangers’ most successful selection in that range over the last 16 entry drafts, they shouldn’t worry too much.

If it’s impossible to know what the Rangers truly have surrendered for 18 regular-season games of Antropov, it’s nearly as difficult to know what Leafs GM Brian Burke sent Glen Sather’s way at Wednesday’s deadline, because Antropov has long been one of the NHL’s biggest mysteries, aside from his 6-foot-6 frame.

Tomorrow afternoon should provide a clue about what the Rangers have when Antropov goes against Boston’s 6-foot-9 Zdeno Chara at the Garden in one of those nationally televised games that have been habitual debacles for Broadway’s team.

If Antropov is aggressive enough to negate Chara, that should create open ice for linemates Brandon Dubinsky and Chris Drury, not to mention the defensemen who jump into the play with the glee of children jumping into a swimming pool on the first day of summer. That will be good news.

For after nearly nine full seasons in Toronto, during which time he was a frequent linemate of Mats (Canucks Are Better) Sundin, Antropov has never been able to match the expectations he’s carried since joining the Maple Leafs as a 19-year-old in 1999.

Instead of becoming Sundin’s sidekick, he too often seemed along for the ride in Sundin’s sidecar, though John Tortorella, Antropov’s new head coach, wouldn’t put it quite that way.

“I think he was in the background; Sundin was everything there,” Tortorella said following yesterday’s brisk practice. “Nik played kind of in the shadow, and when you do that, you may get lost a little bit.

“We want him to be a big part of this team here. We’re going to give him the opportunity not to be in the shadow of anybody,” said Tortorella, who gave Antropov 16:58 of ice time against the Islanders on Thursday. “For us to get where we want to be, Nik has to be there every night for us.

“That’s why we traded for him.”

Even if no one knows what they traded for him.

larry.brooks@nypost.com