MLB

THE GATES OF SELL

ALBERT Pujols suffered a strained left calf on Tuesday and was lost to the wild card-leading Cardinals for at least three weeks. Pay heed, Met Nation. That injury makes it tougher for St. Louis to be identified as the wild Cards.

Get More From Joel On His Hardball Blog

Pujols’ injury should be a reminder that every NL team is operating on a pretty thin line, except perhaps the Cubs. The Mets should know this. Here is something else they might want to know:

When play began a year ago today, the Mets, Brewers and Padres led divisions, and the Dodgers led the wild card. None made the playoffs. But the Cubs, who were five games under .500, won the NL Central, and the Rockies, who were .500, won the NL title.

For the purposes of this exercise, let’s concede the NL divisions to their current leaders: Philadelphia, Cubs and Arizona. Is there any reason why the Mets can’t emerge as the wild card over a mediocre field that includes the Cardinals, Brewers, Dodgers and Marlins?

The Mets should know from mournful experience that if 17 games left in the season is enough time to blow a seven-game lead, then 3½ months is enough time for them still to save their season. But their current plight did trigger two questions:

1. If the Mets are contenders a month from now, should they use their lacking farm system to try to bolster this roster at the risk of further undermining their future?

2. If they are just fringe contenders, should they think of being sellers in late July?

Let’s take them one at a time:

SHOULD THE METS BUY?

When asked about this, General manager Omar Minaya said, “My history is not to trade to catch up.” That is not exactly correct. Minaya’s worst deal came on June 27, 2002, as then Expo GM with Montreal 6½ games back in the NL East and five back in the wild card. He obtained Bartolo Colon from Cleveland for Grady Sizemore, Cliff Lee and Brandon Phillips.

The Mets insist they have a lot of prospects, a perception not seconded throughout the industry. Their best prospect, Fernando Martinez, gets wildly different reactions from outside officials, swinging from future fourth outfielder to future star. One NL executive said, “Martinez is more hype than ability.” And the Mets’ other prospects closest to the majors – closer Eddie Kunz, first baseman Mike Carp and lefty starter Jon Niese – are at least a grade down from Martinez.

So there are questions about how much the Mets could buy even if they opted to buy. Kunz is perhaps the only one from the group who could help even by the beginning of next season, and the Mets already have the majors’ oldest roster. To deal more prospects would only worsen the Mets’ current status: Too much age, too much fragility and too little organizational depth to support it.

SHOULD THE METS SELL?

Every executive spoken to said no chance the Mets sell because the Wilpons have too much invested in this season ($140 million payroll, SNY and a new stadium next year) to ever admit surrender. But the Mets really should be thinking about significantly changing the roster that has brought so much distress while building up their volume of prospects/players-under-30 so as to go into that new stadium in better future shape than they are in right now.

It is ridiculous to consider moving Jose Reyes, who along with David Wright are the long-term building blocks. But the Mets should see which teams that need a big-time center fielder and/or run producer such as the White Sox, Cubs, Cardinals and Dodgers, and maybe even the Yanks and Red Sox, would give up for Carlos Beltran. With the Dodgers, the Mets might need to take back a Juan Pierre or Andruw Jones to balance contracts/center fielders, but if that allowed the Mets to get the Dodgers to consider building a package around James Loney, Matt Kemp and/or Chad Billingsley, they should consider it.

Even with his recent failures, Billy Wagner maintains allure for contenders needing a closer. Milwaukee, for example, is loaded at Double-A, and if the Mets would take a contractual counterweight such as Billy Hall, they might be able to get a deal built around a prospect such as Matt LaPorta or Mat Gamel.

They should investigate if a team in need of a starter (Milwaukee, Florida, Houston) might be interested in giving up a decent prospect or two for a half-season rental of Pedro Martinez (who like Wagner and Beltran would have to waive no-trade provisions). The Mets also would have to see if there is a team that believes a change of scenery would restore Aaron Heilman (some clubs still see him misused and would be obtaining him to put in the rotation next year). A lefty specialist such as Scott Schoeneweis also could have some value (the Yanks wanted Schoeneweis as a free agent and still need a lefty setup man).

The point is the Mets have to be open to the concept that they are just not good enough in 2008, and would be best served improving their future.

joel.sherman@nypost.com