This is the back of a circa 1860 Brooklyn Atlantics baseball card. The pre-Civil War card will be sold at an auction July 30.

NEW YORK — For decades, a circa 1860s Brooklyn Atlantics team baseball card was stored inside a secret drawer of a bedroom set and then between the pages of a photo album.

Now the pre-Civil War card that’s been in the same family for over 150 years is going on the auction block where it could bring $50,000.

Heritage Auctions is offering it on July 30 at its Platinum Night Sports Auction in Chicago held in conjunction with the 2015 National Sports Collectors Convention. Online bidding opened today.

The seller is Florence Sasso, of Great Barrington, Massachusetts, whose great-great-uncle, Archibald McMahon, was an outfielder for the squad. He’s pictured in the photograph with eight teammates.