Now that Mike Piazza has declined into the vale of years, having formally announced the end of his 16-year major league career yesterday, it’s time to state as fact what’s long been plainly true: With the possible exception of Negro League legend Josh Gibson, Piazza was the best catcher in baseball history. It was a privilege to watch him play in New York for so many years, and one can only hope that when he’s immortalized in bronze at Cooperstown, a Mets cap will be perched atop his head, right there with his mullet and moustache.

From his ruthless hammering of the Yankees to his apocalyptic hot streaks (he hit .430 AVG/.509 OBA/.790 SLG in his last 29 games in 1998 as the Mets chased a playoff spot), from his run-ins with Roger Clemens to his game-winning home run in the first sporting event in New York after September 11, 2001, from the press conference he announced to proclaim his heterosexuality to the image of perfect stillness and balance he left with the fans as he launched warheads to right field, Piazza seared his mark on New York baseball. Still, I honestly don’t feel that even rabid Mets partisans have a sense of just how monstrously good he was.

The vast distance between Piazza’s hitting and that of all other catchers ever is staggering, almost impossible to describe, and was remarkably unappreciated in his prime. In 1997 he hit .363/.431/.638 while playing his home games in Dodger Stadium, which damped offense by 7%, which would have been worthy of an MVP award if he’d been a first baseman. Somehow voters picked Colorado’s Larry Walker, a right fielder who played his home games in Coors Field, which inflated offense by 22%. Rather than idiocy on the part of the writers who vote for the award, I’ve always thought this reflected disbelief.

Piazza’s numbers were so preposterous that baseball couldn’t really absorb their meaning. From 1993 to 2002, which isn’t an arbitrary selection — it’s the decade from his debut to the beginning of his physical breakdown — Piazza’s OPS+ was seventh-best in baseball, essentially tied with those of Manny Ramirez, Jim Thome, Gary Sheffield, and Albert Belle. His hitting would have been Hall of Fame-class had it come from a first baseman or a left fielder; with the possible exception of Johnny Bench, he’s the only major league catcher ever of which this is true.

To say that he towered over the competition with the bat is a gross understatement, and his career home runs record for catchers (he’s the only one ever to top 400) is the least of it. In that 1997 season, for instance, Piazza was credited with 150 runs created. No other catcher has ever topped 129, and only four others — Gabby Harnett, Roy Campanella, Bill Dickey, and Bench — ever topped 120. They all did it once; Piazza did it four times. Going by adjusted OPS+, which, like runs created, is available at baseball-reference.com, Campanella had three seasons that would have cracked Piazza’s top seven, Mickey Cochrane had two, Bench and Dickey hadone apiece, and Yogi Berra had none. And while Piazza played in a hitter’s era, he played in the worst hitter’s parks of his day, against the toughest competition in the sport’s history.

This is the point where one is supposed to acknowledge that while all this may be so, defense is the most important part of a catcher’s job, thus somehow making Piazza much the inferior of several other players. This involves hoodoo. Given levels of competition, Bench, a legendary defender, was probably the second-best-hitting catcher ever. He created 93 runs per 162 games — an astounding 23 less than Piazza, in a career of equal length. Was he really 23 runs better per year than Piazza with the glove? It’s possible, but the burden of proof would be on the person making this extraordinary claim. Excepting the odd freak season, there’s little reason to think that the best catchers are worth much more than 10 runs above average per year, or the worst much more than 10 below. Credit the two at these poles, and it still doesn’t make up the difference in offense.

What’s more, Piazza, despite falling victim to the well-known fallacy by which a catcher’s defensive reputation declines inverse to his offensive numbers, was a perfectly decent catcher. He was lousy at throwing out runners, but then he was playing in an era when the stolen base was more or less irrelevant, and he was solid or better at other aspects of the game before his body began to fall apart. Anyone arguing that he was uniquely bad has to explain why his teams routinely won 90 games and why he generally caught excellent pitching staffs. Of how many bad catchers are these things true?

If Piazza was even merely a below-average defender in his prime — and I think that’s a fair way to put it — he would be the best major league catcher ever; he was that good a hitter. That he brought so much more to the game, from cheerfully semi-competent heavy metal drumming to absurd facial hair to a Mets pennant to the wonderful (if moderately suspect) legend of how a 62nd-round draft pick turned himself into one of the best players of all time, just made him all the more beloved.

No Met has worn no. 31 since his last game with the team, in October 2005; doubtless no Met will ever wear it again.

tmarchman@nysun.com