Xavier McKinney, Jason Pinnock give Giants top-notch safety tandem with uncertain future

It could be the start of something special or the end of something small.

One of the unique aspects of the Giants’ defense is the interchangeability of safeties Xavier McKinney and Jason Pinnock, and it has shown up in the negative plays created over the past four games, when the duo combined for 53 tackles, two interceptions, two fumble recoveries and a sack.

“I think that’s big time,” defensive coordinator Wink Martindale said. “If you have two safeties that can play either way — down in the box or back deep — that’s an advantage with disguises and things like that.”

Whether the Giants have discovered a building block entering next season or not depends on whether McKinney is retained — via the franchise tag or a multi-year extension — or allowed to leave in free agency.

Just six NFL teams have multiple safeties — McKinney (No. 9) and Pinnock (No. 30) — graded among this season’s top 30 by Pro Football Focus.

“It’s been great playing with J.P.” said McKinney, who previously told The Post that his free agency won’t be determined by money but by where he can achieve greatness. “As we are going through the weeks, we’ve been able to build chemistry. He has great instincts for getting to the ball.”

Pinnock, who is signed through 2024, can’t help but think that he and McKinney “easily” will be one of the league’s best tandems if the Giants decide to keep them together.

“I don’t have any say, but the complement is rare,” Pinnock said. “The plays I know we’re capable of making will happen. Our communication has been good from the jump as far as our looks, whether it’s two-high safeties, one-high or rotational things.”

Whereas most defenses have a defined free safety to roam center field and strong safety to crash the run, look at these snap totals by pre-snap alignment for the Giants: free safety (Pinnock 593, McKinney 410), box safety (McKinney 303, Pinnock 149), slot cornerback (McKinney 130, Pinnock 107), defensive line (McKinney 60, Pinnock 56) and wide corner (McKinney 22, Pinnock 15).

Imagine being an opposing quarterback trying to decipher blitzes and coverages when those responsibilities can change from one play to the next.

“We don’t have one guy who is always the down guy. We don’t have one guy who is always the blitzer so if he ever gets to the line of scrimmage, you know what’s coming,” defensive backs coach Jerome Henderson said. “We have two blitzers, two guys who can play deep, two guys with range, two guys who can cover the tight end. It gives Wink a lot of fun toys to play with.”

Pinnock is the third different primary safety starting next to McKinney in as many seasons. The former cornerback’s development has been one of the season’s few bright spots — and he credits a lot to McKinney and Julian Love, his predecessor in the versatile safety role.

“Wink is aware that, ‘Right now, I have two safeties that have ball skills,’ ” Pinnock said. “You [an offense] have to respect it. Man-to-man, off the edge, whatever he calls, we can have good ball disruption.”