Jae C. Hong/Associated Press

While it's still anybody's guess as to whether or not ex-UFC heavyweight champion Brock Lesnar returns to the Octagon this year, his former head coach believes the 36-year-old still has what it takes to hang with the best in the world.

The head coach of the now-defunct Death Clutch gym in Minnesota, Greg Nelson, went into detail on the situation during an appearance on the latest edition of Sherdog Radio Network's Beatdown show:

If he came back and he was 100-percent mentally in the game, knowing that he could take whatever it meant to take, he could push himself, he could get hit, he could whatever -- that was the big thing. When he was mentally on, I mean, literally, like his moniker when he was a college wrestler, he was like a freight train. He just was going to go through anything. If he came back and he was mentally 100-percent there, I believe physically he still has the gifts and he still has the ability to improve and to grow, but it’s like anything. The game is such a mental thing that once that chink in the armor was there and that kind of embedded itself in his head, I think that was really the point where it was tough for him.

UFC president Dana White confirmed last week that Lesnar indeed could be making a return to the cage, though he stopped short of saying anything definitive, per MMA Fighting.

The former WWE heavyweight champ retired from mixed martial arts in December 2011 after back-to-back TKO losses to Cain Velasquez and Alistair Overeem.

Lesnar has since made a return to the ring on a part-time basis shortly after the UFC 141 loss to Overeem, where he is now currently feuding with The Big Show.

Despite only a 5-3 record as a professional mixed martial artist, Lesnar managed to capture UFC gold in just his fourth pro bout in November 2008 when he defeated Randy Couture via TKO at UFC 91.

Lesnar was a standout wrestler, earning two-time All-American honors when he wrestled at the University of Minnesota in 1999 and 2000. He also briefly made the practice squad for the Minnesota Vikings in 2004 and 2005, so there is no question he is a special kind of athlete.

However, after two bouts with the stomach disease diverticulitis, which cost him 12 inches of his colon, it's up in the air how much gas Lesnar still has left in the tank.

Is a Lesnar UFC comeback truly on the horizon, or will he opt to stay within the confines of his WWE contract at the end of the day?

John Heinis is a featured columnist for Bleacher Report. He is also the MMA editor for eDraft.com.