If the Mets are to trade Noah Syndergaard then they need to complete the kind of deal that netted them Noah Syndergaard.

When this organization makes a talented starter available it evokes the worst visions for despondent fans of Nolan Ryan and Tom Seaver walking out the door, and Jim Fregosi and Doug Flynn walking in.

But the Mets did trade a Cy Young winner after the 2012 campaign with far less leverage than they have today with Syndergaard, and received two key pieces for their 2015 NL championship in Syndergaard and Travis d’Arnaud.

R.A. Dickey was 38, a knuckleballer, due to be a free agent following the 2013 season and there was no ongoing pennant race to intensify bidding, yet Sandy Alderson landed the key piece he wanted, which was actually d’Arnaud, while meeting the criteria of his trade demand, which was a second high-end piece: Syndergaard.

Syndergaard doesn’t turn 27 until next month, has the highest fastball velocity of any qualified starter, can’t be a free agent until after the 2021 season and the current market has few teams offering high-end starters and lots of contenders needing that entity. That would demand a huge return and that is what the Mets are pursuing. As of Sunday afternoon they were still portraying that teams have not reached their bar for a trade.

Among the interested clubs are the A’s, who have a senior advisor to baseball operations with major intel on Syndergaard: Alderson.

The frontrunner for Syndergaard remained the Padres, though Mets officials were expressing that San Diego — despite its prospect abundance — still had not offered enough.

If the Mets deal Syndergaard they must land no fewer than two high-end prospects and at least two more talented lottery picks. But there are land mines:

1. The Padres’ system is stacked, but multiple executives say that the top 100 prospect glean on many San Diego farmhands outstrips projections. The Mets have to avoid their penchant for prioritizing winning the press conference rather than the trade. Translation: It can’t just be about bragging, “look we got three top 100 prospects,” but getting the right prospects.

Last year the Padres cashed in closer Brad Hand and set-up man Adam Cimber to the Indians for just Francisco Meija, who was high on top prospect lists. But many executives around the league warned Meija’s reputation was better than his game, and Mejia has bombed with San Diego. Luis Urias, generally viewed as San Diego’s top position prospect, is a youngster who gets widely different reviews from evaluators from glowing to good but not great.

Urias is viewed as available, but San Diego’s top two pitching prospects, MacKenzie Gore and Luis Patino, are not. Gore might be the game’s best pitching prospect, so that is understandable. But should Patino be in play?

2. A few teams have mentioned the possibility of the Mets redirecting a valued prospect who does not fit their current needs like Urias (unless they think he can play shortstop and not just second) for a starter who is not free until after next season — Marcus Stroman, Robbie Ray and MIke Minor.

They would essentially be trying to thread what outside executives say is an extremely difficult needle: acquire some players to try to win now plus prospects to win later. And only the top Met officials know the full canvas of what could be acquired for Syndergaard, Edwin Diaz, Zack Wheeler and Jason Vargas.

I do know the Mets tried the win now/win later approach at the 2004 deadline to destructive results when they obtained Kris Benson and Victor Zambrano in separate trades and most notably undervalued Scott Kazmir in trading him. Then they were trying to hold their fans’ attention and give off the whiff they were not surrendering, just as they would want to do now. Usually, it is better to pick a lane and concentrate on that rather than serve multiple masters.

And part of the trade of Kazmir in 2004 was that he was not beloved in the organization, just as that was a factor in dealing Dickey. And while the Mets will insist all is good with Syndergaard the outside perception is that he was available last offseason and again at this deadline, in some part, because the relationship is not great.

3. Teams dealing with the Mets describe diligence — that Brodie Van Wagenen is engrossed in gathering info and creating scenarios — but also concerns if the Mets are slowing down the market with Diaz and Syndergaard and will only move Wheeler and Vargas.

To pull off mammoth trades well, organizational unity and self-belief are needed. Suitors are not sure the Mets, for example, are confident at the highest levels they will best maximize Diaz and Syndergaard, in part because Van Wagenen’s first foray into acquisition last offseason did not go well.

Because the returns in this environment should be terrific and because it is Van Wagenen’s makeup to be engaged and bold, many executives still expect the Mets to be the biggest sellers by Wednesday’s 4 p.m. deadline.

Yet, the institution that is the Mets gives many suitors pause that they will consider, consider and consider and then just pass on the big deals.