The Mets’ June cruise has not only made them relevant in the National League pennant races, but subsequently also at the July 31 trade deadline.

With management believing this is no fluke and the Mets will continue to play alert, aggressive baseball, there are serious discussions not whether they should trade, but whom to trade for – and just as important, whom they should not trade.

Their interest, despite this remarkable run by the rotation, must remain pitching. First rotation; second bullpen.

There is a sense of calm derived from how well Johan Santana and Mike Pelfrey have pitched, and a feeling of optimism with Jon Niese’s run since coming off the disabled list.

Slots four and five are a house of cards.

R.A. Dickey, despite being sterling since coming up from Triple A, is sailing unchartered waters. There’s every reason to think, until he does this for another six weeks or so, that the magic dust might be blown off that dancing knuckler.

Afterall, the Mets have these few starts as a frame of reference, not a lengthy resume.

Hisanori Takahashi is pitching well overall, but has shown some cracks. Plus, he’s better suited for the bullpen, which, as a side note is getting a much deserved break during this stretch after being run into the ground in April and May.

And, seriously, who is really counting on John Maine and Oliver Perez? I mean, beside their mothers?

There are two names out there that stand out like neon on a dark night: Roy Oswalt and Cliff Lee.

Either would look good in Met pinstripes. Because of the length of his contract (through 2012 with the option) the Astros don’t have to trade Oswalt. Consequently, he carries more value to the Astros to the Astros than Lee does to Seattle.

Because the Astros hold some leverage, he’ll cost the Mets a lofty price in prospects, plus the $39 million remaining on his contract if they pick up the club option.

Lee, however, will cost only prospects and the balance of his $8 million contract. Lee, however, has repeatedly said he wants to test the market, and reportedly that could mean as much as $23 million, which is Santana and CC Sabathia-type money.

Do the Mets really want to pay that much? I’m thinking no, even if it means draft choices in return.

However, reportedly the Mets are more interested in Lee than Oswalt, and depending on the prospects demanded, could opt for the rental.

For prospects – and they can’t all be high end if the Mets accept Lee moves – for a chance at October is worth it.

Seattle wants young pitching in return, which means either Niese or Jenrry Mejia. Both are too important to give up for a rental, plus if the Mets are thinking they could contend, dealing Niese for pitching makes no sense because they would still need to add a pitcher.

They aren’t going to trade a promising lefthander who already has tasted success and comes on the cheap for somebody who’ll be at LaGuardia moments after the season ends.

There are other intriguing options, such as Arizona’s Dan Haren, who’ll cost prospects and the balance of his contract, which is in the second year of a four-year (plus 2013 option) for $44.75 million package.

Other options to explore are Cleveland’s Fausto Carmona and Jake Westbrook, or Oakland’s Ben Sheets. Oswalt and Lee are better, but far more costly, especially if the latter bolts.

As much as I believe Mejia should be in the minors learning to be a starter, I wouldn’t want to deal him for Lee unless I could sign him. I would be more willing to deal him for Oswalt or Haren, pitchers who figure to be here for several years.

In the end, I’m figuring the Mets to pursue Lee but eventually settle for a second tier arm.

I think they’ll keep both Niese and Mejia, but might have to deal from this group: Ruben Tejada, Josh Thole, Dillon Gee and Fernando Martinez. 

John Delcos has covered Major League Baseball for over 20 years, including more than ten in New York on the Yankees and Mets beats. You can read Delcos on his blog, New York Mets Report, where he hosts a chat room for each Mets game.