Lennon: Mets need a new ace and his name is Cliff Lee

It no longer makes sense to burn through brain cells trying to unlock the mystery of what may or may not be wrong with Johan Santana. The key for the Mets now is to accept Santana for who he is, and that is a .500 pitcher who was badly outclassed by Carl Pavano in yesterday's 6-0 loss to the Twins at Citi Field.

Pavano is having a great season - he's essentially been Minnesota's ace - and now has thrown back-to-back complete-game victories over Santana and the Phillies' Roy Halladay. There's no shame in losing to him, even with his Boogie Nights mustache.

But the Mets need to realize that Santana, even with two Cy Youngs on his resume, is incapable of carrying the heavy burden that comes with being the No. 1 starter on a contending team.

Regardless of whether he's tipping his changeup or still recovering from last September's elbow surgery or distracted from last week's unveiling of his alleged golf-course shenanigans, it doesn't matter why.

"That I wouldn't know," Mets manager Jerry Manuel said of the latter issue. "It's not my area of expertise. All I know is that when he gets out there, he competes. I didn't notice anything in his demeanor that would indicate that was an issue for him."

Santana may look the same, but that's about it. The bottom line is that the next three months are going to be a dogfight in the National League East, and with the Mets right in the middle of that snarling pack, they need a genuine killer at the front of their rotation. And that pitcher is the Mariners' Cliff Lee.

Lee is the ace that Santana used to be, the one the Mets believed they were getting when they sent four supposed prospects to the Twins and locked him up with a six-year, $137.5-million contract that runs through 2013. Although Santana has held up his end of the bargain more often than not, the Mets failed to reach the playoffs in his first two seasons, and he's wound up on the operating table twice.

The Mets can't let it happen for a third straight year, and the closest they can come to guaranteeing that is doing what it takes to acquire Lee, who is 6-3 with a 2.39 ERA for the lowly Mariners. He's been averaging nearly eight innings per start, has 76 strikeouts to go with only four walks, and boasts a stunning 0.912 WHIP.

Best of all, there's a pretty good chance Lee would be highly motivated to take down the Phillies, who abruptly shipped him to Seattle in the three-team trade for Halladay.

"Can you imagine going into Philly with Lee, Santana and [Jon] Niese?" one Met said after yesterday's game. "There's no doubt Lee would love to . . . "

The rest of that statement had to be censored, but you get the idea. The general opinion in the Mets' clubhouse is that they need a game-changer like Lee, and not one of the middle- tier names available such as Kevin Millwood, Jake Westbrook and Fausto Carmona.

No offense to those three, but who says any of them will be a serious upgrade from R.A. Dickey or Hisanori Takahashi?

Obviously, the cost for Lee is going to be relatively steep, even for a half-year rental. But as long as the Mets keep the foundation of their major-league club intact - and that means not trading Angel Pagan - they should be able to package some talent around Jenrry Mejia that could bring Lee to Flushing.

Saying goodbye to Mejia will not be easy, but chances are he won't be ready to help the Mets this season, and they desperately need to cash in on this early momentum. It's been almost four years since Carlos Beltran took that called third strike in Game 7 of the NLCS, and the Mets haven't been back to the playoffs since.

"You only get so many chances," another Met said.

The Mariners are trading Lee. That's going to happen. And no other team needs him quite as badly as the Mets, for a number of reasons.

Santana just happens to be one of them.