"That's when collecting trading cards was huge," Gronkowski told FOX Business. "That was at its peak and then it kind of dipped a little bit, and now it's at its super peak." "My buddy was a big collector throughout my career, and he was buying cards on eBay of myself," Gronkowski said. GET FOX BUSINESS ON THE GO BY CLICKING HERE"If I ever pulled like a one-of-one, or even a number like a one-of-10 Michael Jordan card, that would be absolutely legendary," Gronkowski said. "I don't even know if it's possible anymore or not, but a Michael Jordan pull, a numbered Michael Jordan would be my ideal pull."