Gronkowski said he met with coach Bill Belichick to inform him of his intention to return, adding he's "been working out, staying in shape and feel great."
"This horse is a winner and I love a winner," Gronkowski said Wednesday. "When I heard about the racehorse being named after me, I started watching and got really stoked when he started winning. He's won his last three and is now headed to the Derby. I'm all in: Welcome to the Gronk family, Gronkowski the Horse!"