Since July 1 last year, the Mets are 64-62, which is only embarrassing if you take into account that they’re the most talented and best-paid team in the National League. Everyone who cares has their own theory on how this has happened, but whether they blame bad managing, old and injury-prone players, bum relievers, a lack of team depth, bad vibes in the locker room, or several (or all) of these factors, one thing all seem to agree on is that much of the fault comes down on shortstop Jose Reyes, who stopped being himself a year ago and hasn’t started since.

When napping in the field and on the bases or weakly grounding out to second base, Reyes is one of the more frustrating players in baseball, especially because nearly all his mistakes are avoidable, which is why he gets so much grief. Still, no matter how aggravating he can be, the idea that he bears any real blame for the Mets’ mediocrity is ridiculous, another instance in the long history of excellent players being blamed for the failings of their lousy teammates.

It is true that Reyes’s game went into notable decline about a year ago. From last July 1 up to the beginning of last night’s game against Atlanta, Reyes hit .268 AVG/.334 OBA/.414 SLG with 61 steals in 81 tries; over the preceding year, he’d hit .322/.383/.510 with 73 steals in 90 tries. Many explanations have been offered for this: that Reyes has been sulking over his contract, that he was ruined by Rickey Henderson’s brief stint as the Mets hitting coach, that he lost his mojo after ceding to demands that he stop acting so exuberant on the field, etc.

There is, of course, a simpler explanation: gravity. Between July 2006 and July 2007, Reyes hit like Atlanta first baseman Mark Teixeira (career line: .285/.370/.532) while playing as well in the field as anyone in baseball and running better than anyone. If he was able to keep that up for several years, he’d end his career acclaimed as one of the five best shortstops of all time; it’s no real knock on him to say that he hasn’t been able to do it. And while Reyes hasn’t been hitting like a young Alex Rodriguez over the last year, he actually has been pretty good. Since July 1, the NL as a whole has hit .267/.336/.426 — not a lick better than Reyes has hit. Even in the modern game, a shortstop who hits at the league average is pretty valuable. When that shortstop is also a magnificent defender and the game’s best base runner, one might even surmise he’s helping, not hurting, his team.

By any reasonable standard, Reyes has developed into a devastating player. Over a full year in which more or less everyone would agree he’s been in a long, awful slump, Reyes has put up a batting line comparable to the career lines of star shortstops ranging from Pee Wee Reese to Jimmy Rollins. If one definition of a great player is someone who plays like a star even in a long funk, Reyes is a great player.

If he seems at times like an agitated teenager rather than a star, that comes down to the gulf between what he’s doing and what he should be doing, which is splitting the difference between what he’s hit over the last year and what he hit over the year before that. That would leave him with something like a .300/.360/.460 line, or about what Barry Larkin hit in his career. There’s no reason to think he won’t get there, and while the wait may be irritating, the payoff will make it worthwhile.

This is because the difference between Reyes hitting as he is right now and hitting like Larkin is basically 30 points of batting average — less than a hit a week over the course of a season. Reyes is effectively the fastest runner in the league, walks a lot, and strikes out rarely; there’s really no reason at all that he shouldn’t be hitting .300. It’s just a matter of swinging at fewer pitches he can’t drive, or making a minor technical adjustment that would turn the odd 4-3 groundout into the odd flare, grounder with eyes, or dying quail. (All of this is easy for me to say.) The man isn’t even 25 yet. He’ll figure this out, and he’ll have many more long stretches of hitting like an All-Star first baseman over the rest of his career.

While they’re waiting for him to do so, shirt-tearing Mets fans ought to ponder how absurd it looks when Yankees fans tear Rodriguez down, as if their team’s various miseries and failings were his fault, rather than those of his infinitely less talented teammates; slagging off Reyes isn’t as absurd, but the difference is one of degree, not kind. There’s a lot of blame to go around in Queens for a year of uninspired and at times inept play, but very little of it sticks to the shortstop. He isn’t yet what he can and likely will be; he is, though, one of about four players who have made the difference between this being a maddening team and it being the worst team money can buy.

tmarchman@nysun.com