The Mets, it is clear, are determined to give their fans heart attacks this year. Yesterday, not a week out of first, they lost the last game of a three-game sweep to the Houston Astros, 4-0, which left them in third place, 2.5 games behind Philadelphia. Closer Billy Wagner, already fighting shoulder woes, was unavailable for the game because of a strained left forearm, and will go in tomorrow for a second MRI test in two weeks. Going from worse to worst, starter John Maine was placed on the disabled list with a strained rotator cuff, nearly the last injury you want to hear that a pitcher has.

If the team had a bad day, so did the star center fielder. Carlos Beltran, batting no. 2 for the second time this year, was picked off in the first and made three outs with men on, including the last out of the game. In all, he went 4-for-13 with a walk and two runs scored in the series — not bad, but not enough, which sums up the world’s reaction to Beltran’s play this year. During the All-Star break, five times as many Metsblog.com readers voted to give him a “C” on the season as voted to give him an “A”; since, he’s hit .258 with no home runs. Prominent columnist Mike Lupica even called him “the biggest offensive disappointment in town” yesterday. If he’d been shipped out of town at Thursday’s trade deadline for Jason Bay, half of New York would have cheered.

What’s strange about this, of course, is that Beltran is having yet another superb season, on a team full of players doing a lot less than that. The Mets, both as a team trying to win a pennant and as an organization, have many serious problems. Even on a bad day, Beltran doesn’t rate in the top 50.

Beltran isn’t, true, having the kind of season he had two years ago, when he hit .275 with 41 home runs and 127 runs scored. No one hits like that every year — they call you Mr. Mays if you do — but by any other standard he’s fine. He’s hitting .266 BA/.364 OBA/.453 SLG; the average National League center fielder is hitting .261/.328/.417. That’s good. If every Mets hitter was that much better than average at their position the team would score 925 runs and win the pennant every year.

This is, though, of all players in the sport, one of those you least want to judge just by his offense. Have none of his many detractors noticed that he’s one of the most complete players in baseball? He’s one of the best defensive players in the game at one of its most important positions. He’s allowed the team to get by with revolving doors of second basemen and designated hitters at the corners for years because of the ground he covers. He’s one of the best base runners in the game, too. He even does all the vaunted little things at the plate: He’s exceptionally patient, bunts for base hits, fouls off pitches, hits to the other side, and all the rest of it. Judging him by his batting line is a little bit like judging Jason Kidd by his scoring average.

According to the Fielding Bible’s plus/minus system, which scores defense play by play, Beltran has made 15 more plays than an average center fielder would have in the same chances this year, third in baseball. According to Bill James, who tracks baserunning play by play, Beltran has picked up 20 extra bases on the year, including base stealing and general running — as many as Jose Reyes. These aren’t flukes — Beltran ranked second in extra plays made last year and seventh the year before, and he’s picked up between 32 and 36 bases every year he’s played at Shea. (These numbers are available via James’s online subscription site.)

Cutting off a double in the gap with a spectacular running catch or reaching home from first, which Beltran has done five times in seven chances, are tangible actions, every bit as real as hitting a home run, and he deserves credit for them. If you made Beltran a slightly below average defender and base runner and added 30 singles to his batting line, he’d be hitting .338/.424/.537 right now, no more valuable than he actually is, yet he would be the crowned king of the five boroughs. That he isn’t doing that, but instead contributes in every way there is to contribute, doesn’t make him less than what he is: One of the best players in baseball let alone New York, and the man who will deserve as much credit as anyone else if the team actually pulls the season out in first.

tmarchman@nysun.com