NEW YORK – Brian Cashman’s opening bid was a solid play, getting the lefty-hitting outfielder Andrew Benintendi and lengthening the Yankees’ lineup.

Now comes the hard part.

How much of a prospect haul will it take to get Luis Castillo out of Cincinnati and into the Yanks’ rotation?

If it takes shortstop Oswald Peraza and another top-five prospect - not named Anthony Volpe or Jasson Dominguez - the Yanks should strike that deal.

And there’s plenty of depth in the system to get a quality reliever or two before Tuesday’s MLB trade deadline, though finding a match in a competitive field of contenders is never easy.

So, good on the Yankees for completing this early play for Benintendi – a free agent at season’s end – in exchange for three minor league pitchers not among their top 15.

The move for Benintendi also mercifully ends Joey Gallo’s tortuous Bronx run.

Any minute now, the Yankees will surrender on the lefty slugger who batted .160 over 138 games in pinstripes, with a .664 OPS with 191 strikeouts in 418 at-bats.

Friday is the anniversary of Gallo’s trade last year, along with lefty Joely Rodriguez, from the Texas Rangers for four prospects.

Rodriguez was traded to the Mets for reliever Miguel Castro, currently on the IL with a shoulder strain and possibly sidelined until September.

Yeah, that one didn’t work out so well, with Gallo now in his free agent walk year.

But the trade for Anthony Rizzo, swung on the same day last year, had caused a celebration on the Yankees’ charter from Tampa to Miami – except in Luke Voit’s row of the plane.

Honestly, both moves were seen as a needed jolt for a club that was desperate for some lefty-hitting offense.

Only the Rizzo move worked out, and well enough that the Yanks re-signed him as a free agent.

YANKEES LINEUP:Here's what it looks like now with Andrew Benintendi in pinstripes

This is a far better Yankees team than last year's flawed one-and-done wild card entry of 2021.

But they've now dropped 10 of their last 15 games - including Wednesday night's 3-2 loss to the Mets, who swept the two-game Subway Series at Citi Field.

The right spark could go a long way, "especially when you add a guy like that, hitting over .300 all year and playing great defense,'' said Aaron Judge, who ran down Benintendi's scouting report.

"Bat-to-ball skills, speed, always works a good at-bat,'' Judge said of the 2022 All-Star, 2021 Gold Glove left fielder (who can play some center field) and 2018 world champion with the Boston Red Sox, currently batting .320.

And despite just three home runs in 93 games, the Stadium's short porch will be a benefit.

"If you’re not too careful, he can leave the yard – I’ve seen it many times at Yankee Stadium,'' Judge said. "He’s a well-rounded player. I think he’s going to fit right in.''

Speaking generally, before the trade was announced, Rizzo said that "anytime you're adding at the deadline, it's always a boost,'' though, "I love the group in here right now.''

Though the Yanks got some hard shots against Max Scherzer, they still couldn’t score until the Mets’ ace departed after seven innings.

After Gleyber Torres belted a game-tying, two-run homer off David Peterson in the eighth, Starling Marte delivered the game-winning hit off Wandy Peralta (Clay Holmes was used against the Mets’ middle of the order in the eighth).

The Yankees have bowed against elite starting pitching in recent postseasons, and Scherzer’s performance – on his 38th birthday – was another reminder about those lost Octobers.

“He’s one of the best in the game for a reason. You can’t expand too much,’’ said Judge, 0-for-4 against Scherzer with three strikeouts, all on sliders. “Just got to tip your cap.’’

And while Judge offered a hat-tip to Benintendi’s acquisition, it wasn’t official when manager Aaron Boone took the podium.

“If we get him, that’s another really good hitter to add to the mix,’’ Boone said, improving the club’s lineup balance. “I’ll be excited to write his name in.’’

Boone also mentioned that the Yanks would “certainly welcome him and look forward to getting him assimilated.’’

As a player whose unvaccinated status prevented him from travel to Toronto for a recent series with the Royals, it’ll be interesting to see if conforming to life as a Yankee will influence a personal decision.

On the field, Boone said the Yanks were already “equipped to handle’’ the adversity they’ve recently encountered.

“We’re unfazed,’’ Boone said. “We know where we’re going.’’

Rizzo said it’s “part of the 162,’’ and they’ll just “stay the course.’’

Judge said that “we’re still one of the best teams in the game,’’ and they got a little better with Benintendi.

Next on the agenda: Improving a little more with a boost to the pitching staff.