Mets president of baseball operations David Stearns, inset, traded outfielder...

Mets president of baseball operations David Stearns, inset, traded outfielder Brandon Nimmo on Sunday.

The Mets shipping Brandon Nimmo to Texas four days before Thanksgiving isn’t the typical winter upgrade move. Trading your longest-tenured core player and a verified clubhouse leader coming off a very productive season at the plate wasn’t something that necessarily had to be done.

But by sending Nimmo to the Rangers in a swap for second baseman Marcus Semien, as multiple sources confirmed Sunday evening, the Mets revealed one important detail about their offseason strategy: They’re not kidding around when it comes to erasing the stench from last season’s playoff-fumbling debacle.

Zeroing in on Nimmo was a curious place to start. He was nearly everything the Mets could have wanted since Sandy Alderson’s front office picked him No. 13 overall in the 2011 draft. At his best, he was an on-base machine, a diligent worker who was always accountable and a true professional who represented the franchise well, both on and off the field.

That is not an easy combination to find, especially in this market and particularly in Flushing. Just as Francisco Lindor was mentioned recently as a potential captain, some would say the same about Nimmo, who appreciated being a Met and embraced the challenges (as well as the frustration) that came with wearing the blue-and-orange uniform.

Frankly, it’s hard to imagine the Mets without Nimmo. But David Stearns, entering his third — and most critical — season as the team’s president of baseball operations, wasn’t about to let sentimentality get in the way of his winter goals.

Nor should he. Once Steve Cohen capped the Mets’ second-half slide to oblivion with a public apology to the fans who had answered his spring training call to pack Citi Field all summer, you got the sense that Stearns would be operating with extreme urgency this offseason.

Consider Nimmo the first big domino to fall. And based on the timing, there should be plenty more to come, as dealing Nimmo for Semien straight up was as much about future moves as immediately improving the roster.

It’s not as if Stearns hasn’t been telegraphing this blueprint, either. He’s repeatedly cited “run prevention” as his mantra for this winter, and ditching Nimmo’s rapidly declining defense in leftfield for a two-time Gold Glove winner in Semien at second base already makes good on that pledge.

But merely swapping out Nimmo for Semien can’t be the sole motivation, even when the deal involves trading one bloated contract for another. Nimmo is due another $101.25 million through 2030 while Semien has $72 million left over the next three seasons, but the Mets also are sending $5 million to the Rangers to help offset the difference in remaining salaries, a source confirmed Sunday.

Exchanging those two contracts provided the fit the Mets needed to move a relatively immovable player in Nimmo, who agreed to waive his no-trade clause (probably because he wasn’t feeling all that wanted lately). More importantly, it freed up some other options for Stearns, who now has an opening for a corner outfielder and doesn’t really need Jeff McNeil anymore.

That brings two of this offseason’s most coveted free agents into focus — Cody Bellinger and Kyle Tucker — while starting the clock on McNeil, who now can be flipped for something else Stearns has his eye on. Those subsequent dominoes have to be where this trade really pays off, because solely investing in Semien is a pretty big gamble in itself.

He turned 35 in September and is coming off a down year (15 homers, .669 OPS) in which he played only 127 games because of a Lisfranc sprain and fracture in his left foot. He still won his second Gold Glove and is considered one of the sport’s best defenders at second base, but his plate production has slipped significantly since he placed third in the AL MVP voting in 2023.

Will a change of scenery and renewed health turn back the clock for Semien? It’s a dice roll, but it clearly is a risk that Stearns felt comfortable taking, certainly because trading Nimmo was only the first step to whatever else is up his sleeve.

With Nimmo gone and the focus presumably turning to Bellinger and Tucker, the Mets’ desire to shake up the core has only begun.  Stearns’ proclamation about “run prevention”  already put Pete Alonso’s return in jeopardy from the jump. Now, with an outfield spot open, does that mean the bulk of Cohen’s offseason budget will be earmarked for either Bellinger or Tucker, with Alonso having to wait for the leftovers?

One thing’s for sure. Stearns has ripped the Band-Aid off as far as messing with the Mets’ long-standing clubhouse pillars, and the Nimmo trade signaled that mission is well underway. Where that stands on the list of priorities remains to be seen, but it feels like the goal rather than collateral damage.

Nimmo was a good Met for a decade in Flushing, with  the possibility of his No. 9 someday hanging from the Citi Field rafters. Instead, he’s become the trigger for a turbulent winter designed to presumably return the franchise to prominence.

Probably not how anyone would have imagined his career turning out, but the Mets have only one sole directive now — and that’s to make sure what Nimmo was a part of last year isn’t repeated.

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