Mike Piazza -- Jerry Seinfeld's Got a Cannon ... Best Celeb Pitcher

He ain't exactly Nolan Ryan ... but Jerry Seinfeld can BRING THE HEAT ... so says Mike Piazza, who tells TMZ Sports the comedian is the best celeb pitcher he's ever caught.

And Piazza knows what he's talking about -- he caught in the Majors for 15 years ... playing backstop for all sorts of famous people who fired out the 1st pitch before games.

So when we asked him to name the #1 celebrity when it came to mound dominance, Mike didn't hesitate ... and explained why he's got so much respect for Jerry.

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