Walker was cut Monday during training at the American Kickboxing Academy in San Jose, Calif. The injury required multiple stitches, forcing the former running back to pull out of his scheduled Strikeforce fight against Scott Carson in St. Louis on Dec. 4.
"I feel terrible about this," Walker said. "I know things like this happen in all sports, but I had trained very hard and was excited to be returning to the cage again. I hope to fight again as soon as the cut heals."
The 48-year-old Walker has been pursuing MMA since 2007 as the latest endeavor in his eclectic athletic career. The 12-year NFL veteran and former Georgia star also ran track, earned a black belt in taekwondo and trained for the U.S. Olympic bobsled team.
Walker was cut on a knee strike while training with Daniel Cormier, a two-time member of the U.S. Olympic wrestling team. Cormier is among Walker's teammates at AKA, the storied Bay Area gym that has produced UFC heavyweight champion Cain Velasquez and MMA fighters Josh Koscheck, Jon Fitch, Phil Davis, Mike Swick and Josh Thomson.
Although he has no illusions of a grand career in the sport, Walker had hoped to prove he wasn't just an MMA curiosity in his second bout.
Walker said he hopes to fight as soon as the cut heals, which likely will require several weeks.