A Brooklyn US Postal Service supervisor was busted by the feds Thursday, accused of buying and selling thousands of dollars in coveted baseball and other sports cards that he knew were stolen — including cards featuring Yankees legend Mickey Mantle and NBA Hall of Famer Larry Bird.

John Bu, 38, a customer service supervisor at a mail processing and distribution center in East New York, purchased cards he knew where hot from an underling, who he knew had previously been arrested for stealing items from the mail, prosecutors alleged.

Bu pocketed $6,250 in November after reselling some cards — including a Thurman Munson All-Star rookie card and two Mickey Mantles — he “assumed” were stolen to a Westchester dealer, according to a complaint.

Bu initially lied to the feds by claiming he’s an avid collector and made less than $500 selling the cards, the complaint alleges. But he changed his story after being confronted with evidence showing the $6,250 in his bank account paid by the dealer.

He then admitted paying the co-worker — who is listed in the complaint as “John Doe 1” — $7,000 in 2008 or 2009 for a bunch of cards of various players that also included MLB legends Lou Gehrig and Jackie Robinson.

Bu was charged in White Plains federal court with possession of stolen mail and released on $25,000 bail.

He faces up to 5 years in jail.