Former Heisman Trophy winner Herschel Walker is set to make his Mixed-Martial Arts debut on Saturday. Here's a look at the former Georgia Bulldogs star's career, Then & Now.

Walker was a sportswriter's and statistician's dream, a study in athleticism and numbers. After a stellar high-school career, the running back naturally caught the attention of recruiters. In 1980 he suited up for the University of Georgia and became the instant pride of Athens, blazing through the NCAA record books with ease. In 1982, as a junior, he claimed the Heisman Trophy and split for the big time with a trail of historic feats in his wake: 11 NCAA, 16 Southeastern Conference, and 41 school records. Walker proved a natural for the fledgling USFL, guiding the New Jersey Generals, under the auspices of owner Donald Trump, to two winning seasons in three years before the league was dismantled in 1986. Walker then played 12 seasons in the NFL, beginning and ending with the Dallas Cowboys. And did we mention his stint as a bobsledder in the 1992 Winter Olympics?

The tireless Walker remains one of the most active 47-year-olds in America. Last year he was reunited with Trump on a different playing field: Celebrity Apprentice. Despite his talents, Walker proved no match for winner Joan Rivers. So he opted for a less dangerous vocation: budding rookie in Mixed Martial Arts. He signed with the Strikeforce organization and went into training under an intense amount of media scrutiny. He is reported to be in amazing physical condition -- lighter than he was in college -- going into his Jan. 30 heavyweight debut against Greg Nagy, a contender 21 years his junior. But for Walker, age is nothing but a number, and he's been amassing numbers all his life. "Look," he said, "I might be 47, but I don't look or feel like 47. ...I just can't sit still. I have to be doing something all the time."

(Created by Sodahead.com)

More Herschel Walker: Jon Wertheim: Herschel Walker Q&A Sodahead.com: Herschel Walker Survive Cage Match? Sodahead.com: Herschel Walker Training Video SI Vault: Does Herschel have Georgia on his mind? (3.1.82) SI Vault: Herschel Walker stars with New Jersey Generals (5.27.85) SI Vault: Herschel Walker returns to Dallas Cowboys (8.26.96) SI Vault: Herschel Walker: A Renaissance man (10.3.07)

SI Apps
We've Got Apps Too
Get expert analysis, unrivaled access, and the award-winning storytelling only SI can provide - from Peter King, Tom Verducci, Lee Jenkins, Seth Davis, and more - delivered straight to you, along with up-to-the-minute news and live scores.