It’s time for the Mets to fire Willie Randolph. They should fire him if his team sweeps the Arizona Diamondbacks this weekend. They should fire him if his team wins all three games by a total score of 27-0. They should fire him if his team puts on such a display this weekend that the greater Phoenix area literally burns to the ground around them, lit by nothing but the intensity of their passion and brilliance. The man’s time is up, and nothing can change that.

Unless a manager is a genius, all one can ask him to do is not actively harm his team’s chances. Randolph doesn’t pass this test. Under his leadership, the Mets failed to play up to the level of their talent in 2005, did so again last year, and are doing so once again this year. Correlation may not imply causation, and it may not be precisely the manager’s fault when his men are alternately listless, inattentive, and perplexed. When a manager is relentlessly inept at identifying his own best talent, though, and has over a period of several years proven himself completely incapable of seizing advantages during a game — when he’s displayed no feel for strategy or for tactics — he has to be able to inspire his men to play at their best, or better, if he’s to serve any purpose at all.

For a full year now, nearly no one on the Mets has done that. Wednesday’s shameful 13-1 loss to the wretched Pittsburgh Pirates was the pitch-perfect demonstration of the depths to which this team, which a year ago was so vibrant and so promising, has managed to sink. When Oliver Perez walks five in 1.2 innings; when Jose Reyes fails to cover a base on a routine play, and when a strong lineup manages two hits against one pitcher who came into the game with a 13/22 K/BB ratio and another who was a hitter coming out of college and whose two shutout innings lowered his career ERA to 8.74, something is terribly, desperately wrong. These are not random failures of talent, but unforgivable errors of concentration and execution.

The Mets may be winning more than they’re losing, but they’re playing horribly, and things seem uglier the closer you look. David Wright is playing like what he is, the best player in the league; Johan Santana is, the odd long ball aside, proving to be exactly what was advertised, and Billy Wagner has yet to give up an earned run in 11 games. These three, along with outfielder Ryan Church, who’s playing a hair better than expected, are essentially keeping the team from total collapse. It’s a damning point; Randolph should not receive too much credit for getting these Hall of Fame-caliber talents to play well.

On the other hand, several other Hall of Fame-caliber talents are playing miserably, and in ways for which it’s perfectly fair to blame the manager. Reyes has more closely resembled Cristian Guzman than he has Barry Larkin for some time now, Carlos Beltran is slugging .398, and Carlos Delgado seems to be about done. Their struggles seem, respectively, to have to do with concentration, aggressiveness, and an inability to adjust to what happens as you age. A manager of no special mechanical cleverness, who doesn’t help put runs on the board with his mastery of the nuts and bolts of calling signals, making out lineup cards, or calling for the right relief pitchers, who can’t help players deal with these airier, more abstract concerns, is a nearly useless one. That’s what Randolph has become.

Hard times are coming for the Mets. In addition to all the problems with the offense, the credible performance of the team’s rotation has been largely phantasmal. John Maine’s shiny 3.58 ERA masks his more telling walk rate of 5.58 per nine, Mike Pelfrey is striking out 4.03 per nine and walking exactly as many, and Perez seems to be imploding. Unless something changes radically and soon, this team is in for, at best, more of the same mediocrity fans have been suffering for a year now.

This weekend in the desert, the Mets are probably going to be flayed. Arizona is everything the Mets seemed to be not long ago — young, sharp, and as driven as they are talented — and they’re rolling out Brandon Webb and Dan Haren, the best one-twon punch in the league, and Micah Owings, a sophomore starter who’s at worst every bit as good as Perez or Maine. Just as happened in Chicago, this team is going to be exposed by the contrast between them and a true winner. And the shame of it is that the Mets have every bit as much talent as the Diamondbacks or Cubs do.

That they haven’t expressed that talent in its fullness is in the end the fault of the players, not the jeering Queens fans, drive time hosts, bloggers, or even the manager. The manager, though, is the one whose sole job is to ensure that the team that physically takes the field is as good as the team that’s on the lineup card. In this, Randolph has failed in concrete ways, and shows no prospect of or capacity for improvement. Every day the Wilpon family and Omar Minaya keep him in his job is a day they do a bit more to show themselves as unfit for their jobs as Randolph has proved for his.

tmarchman@nysun.com