A baseball-memorabilia collector is crying foul.

Corey Shanus, a Westchester lawyer who has amassed a treasure trove of artifacts from the national pastime, filed a $600,000-plus fraud suit yesterday against a dealer he claims duped him into buying two fake balls.

The Manhattan federal lawsuit says Shanus relied on expert advice from Robert Lifson of Robert Edward Auctions before bidding on two “trophy balls” purportedly from the 1800s.

But Shanus says testing shows the balls contained a material introduced in the 1900s.

Barry Kozyra, a lawyer for Lifson, said called the suit “frivolous.”