‘Tis the season for stupid headline puns. Mike Francesa broke news that the Mets agreed to a deal with Jason Bay yesterday, and now everyone’s weighing in.

I’d still really like to reserve judgment until we know more, though. Specifically: the terms of the deal. By all accounts, it’s worth about four years and in the neighborhood of $66 million. By some accounts, it’s backloaded. By most accounts, it’s got a vesting option for a fifth year that will bring it to about $80 million.

That’s the part I’m curious about, and I expect in the coming days we’ll get a much clearer picture as to exactly what that vesting options means. If it’s as easy as Joel Sherman suggests, then I’m not sure why the Daily News is showering Omar Minaya with praise for holding his ground on the four-year deal when that’s, well, not what that is.

I suspect part of the motivation for including the vesting option is just that — maintaining the perception of holding firm while actually compromising with the player — and so good for Minaya if his intention was to convince the Daily News that he was strong-willed.

If his intention was to build the best possible club for the years beyond 2010, though, I’m not so sure the vesting fifth year was the best idea. Nor is a backloaded contract, if that’s the case.

But I’m getting ahead of myself; I’ll whine about the terms of the contract when I know the terms of the contract.

What I know for certain is that Jason Bay is a terrific hitter. He was a terrific hitter in Pittsburgh, and he was a terrific hitter in Boston, and he will likely continue being a terrific hitter in Queens. He mashed pitching in the uber-competitive AL East and returning to the NL should be a relative cakewalk for him.

Sure, he was aided a bit by Fenway’s friendly confines and short left-field wall. But there’s evidence that Citi Field plays well for right-handed pull hitters, and the Mets put out word (through Francesa) that they had data that Bay’s power would play better at their home park than would that of fellow free agent Matt Holliday.

They had me at “data.”

He’s patient, befitting his reportedly quiet professional demeanor. In fact, as I Tweeted yesterday, Bay walked 20 more times last year than Daniel Murphy, Bengie Molina and Jeff Francoeur combined.

He does strike out a bunch, and he’s not a great defender. It’s tough to tell to what extent, since it’s tough to evaluate defense in general and especially tough to judge defense in Fenway Park, as Sam pointed out in the Amazin’ Avenue post I linked earlier. And at 31 and with knee trouble in his past, he’s probably not getting any better in the outfield.

The good news is the Mets have Carlos Beltran, and when he was healthy in 2008 and the Mets began haphazardly trotting out infielders with no outfield experience into their outfield corners, Beltran responded by making an obscene number of out-of-zone plays, clearly deciding that the chumps alongside him had no business catching fly balls when he could do it so much better.

It’s no safe bet Beltran will again be the defender he was in 2008, nor am I certain that his ability in center allows the Mets to sacrifice defense in left, but the combination of a rangy Beltran and a plodding Bay should at least inspire some aesthetically awesome running grabs from the graceful center fielder.

So that’s cool.

Wait, how did this post about Jason Bay become about Carlos Beltran?

Oh, because Carlos Beltran is awesome, that’s why. And now he has Jason Bay in the lineup to drive him in sometimes. So that’s cool, too.