MLB

Mets and Yankees should go after Lee

When Mariners GM Jack Zduriencik obtained Cliff Lee in the offseason, he imagined turning his 85-win 2009 team into a championship contender.

So imagine Zduriencik’s pain in the next few weeks when he is compelled to trade Lee from his last-place disappointment. If an interested team is not prepared to endure equal pain, then it will not get the ace.

Translation:

You are not getting Lee for Fernando Martinez and Josh Thole. That would be painless for the Mets. I don’t know if an injuryprone outfield prospect (Martinez) and a fringe catching prospect (Thole) are worth as much as the two first-round compensation picks an acquiring team would receive if it lost Lee to free agency after the season. So why would the Mariners gift-wrap Lee and those two picks for such a meager return? Flip it; if you ran the Mets would you trade Lee for the equivalent of Martinez and Thole? Of course not.

Thus, if the Mets want Lee — and, boy, do they ever — a trade will have to be built around Jenrry Mejia, whom Seattle likes, but does not love, or Wilmer Flores, an 18-year-old infielder already thriving at High-A. In conversations with Mariner officials, I strongly sensed they would accept no less than one blue-chip prospect or they will not do this trade.

One key impediment for Seattle is that Lee has been traded twice in the past 23 months for seven prospects — none of them blue chip — as teams dealing the lefty valued quantity in return over quality. So now interested teams are going to feel they have to give up even less for Lee since he will be around for just half a season. But, again, I think Zduriencik won’t move Lee without a top prospect in return.

And that should be his strategy. Lee did not have his best stuff last night, yet he still threw a complete game in a 7-4 triumph over the Yanks. He now is 43-19 with a 2.81 ERA since the start of the 2008 season. Plus, he was 4-0 with a 1.56 ERA in last year’s postseason. He is a season changer for any contender. That is why the Mets should do what is necessary to get him and why even the Yanks should be thinking similarly.

The Phillies put Chase Utley and Placido Polanco on the DL yesterday, making the three- time defending NL East champs even more vulnerable. The division is winnable for the Mets. But they need another high-end starter as R.A. Dickey and Hisanori Takahashi showed the past two nights that it might always be close to midnight for them. The Mets are slowly winning back a disenchanted fan base. Lee is a love letter to the faithful, plus a big boost to make the playoffs — and do something once you get there.

The Yanks, meanwhile, have told Zduriencik to keep them posted on Lee, though they do not want to expend prospects and dollars to fix a rotation they do not believe is broken. They prefer to wait and just buy Lee in free agency, and not trade any prospects.

But the Yanks were willing to include Jesus Montero in trade offers last offseason for both Lee and Roy Halladay, who both would have been entering their walk years. They should offer him again for a half season of Lee, as well. Having Lee and CC Sabathia turns the Yanks from World Series favorites into Secretariat. In this scenario, they would not lose a first-round pick if/when they re-sign Lee. They could either put Phil Hughes into the bullpen or try trading Javier Vazquez for a righty-hitting outfielder — though having Lee would remove one of the lefty studs to worry about.

Would it be painful to deal Montero and someone such as Double-A second baseman David Adams, currently on the DL, but a player Seattle does like? You bet. Again, this trade does not happen without pain. But the Yankee farm system is particularly deep in catching talent.

And the Yankees’ mandate — always — is to go for championships. Obtaining Lee — as painful as that would be — makes the potential pleasure of a 28th title more probable.

joel.sherman@nypost.com