Brock Lesnar, the professional wrestler who elevated mainstream interest in the UFC, has opted against a return to mixed-martial arts (MMA).

“The older you get the wiser you become,” the 37-year-old Lesnar told ESPN on Tuesday. “I didn’t want to be that guy who retired and came back.”

In a short but eventful career, Lesnar won the UFC heavyweight championship in his fourth professional fight, a victory over MMA legend Randy Couture. He followed that up with a career-defining beatdown of Frank Mir at UFC 100, the biggest event in the promotion’s history, and a dramatic come-from-behind triumph over Shane Carwin at UFC 116.

But injuries and diverticulitis, a disease plaguing Lesnar’s intestines, noticeably cramped his game in the Octagon before killing his career. Lesnar retired after losing his title to Cain Velasquez in 2010 and then falling to Alistair Overeem’s knees and kicks to the body more than a year later.

Seven numbered UFC pay-per views have reached a million buys. Brock Lesnar headlined three of those cards. The Las Vegas-based promotion and competitor Bellator MMA appeared poised to offer millions to the transcendent mixed-martial artist to compete under their banners.

Lesnar’s decision drew interest in part because of his attendance at UFC 184 and in part due to the expiration of his contract with the WWE. The UFC struggled for several years after Lesnar’s retirement, never quite finding a fighter to generate mainstream interest the way Lesnar did. But a new batch of superstars, including Ronda Rousey, Jon Jones, and Conor McGregor, have reinvigorated interest in the sport in 2015 after a rough 2014.

Lesnar told ESPN that he had been training heavily for a return to MMA in recent months but the passion didn’t accompany the sweat. The current WWE champion, who performs in the ring with Roman Reigns at Wrestlemania 31 this weekend, confirmed a new contract with the outfit: “Last night, old Vince McMahon put the offer on the table that I couldn’t refuse.”

“I could go back to the Octagon, but what am I going to gain?” the only man to hold the WWE and UFC heavyweight championships reasoned. “I was the UFC heavyweight champion of the world. Due to my illness, my career got cut short. That’s God telling you, ‘it’s time to move on.’”