The 6-foot-11, 230-pound Walker, ranked 12th in the Class of 2013 by ESPN.com, said he is currently taking three online classes and is optimistic he will fulfill his academic requirements in time to be eligible at the semester break.
"Now I understand how serious high school is and that you can't take the work lightly," Walker told ESPN.com on Tuesday. "I didn't do as well and work as hard as I should have early in high school.
"It's a minor setback, and every day I'm working hard to get to Florida. My plan is to definitely be at Florida. I'm working every day to make sure I get to Gainesville."
Walker's eligibility issue was reported earlier by CBSSports.com.
Walker is a McDonald's All-American and a part of Donovan's recruiting class this season that also includes talented point guard Kasey Hill -- who could start for the Gators with Scottie Wilbekin suspended indefinitely.
Walker's presence will certainly help the Gators. He's a long and athletic big man who runs the floor exceptionally well and will also give Donovan a big-time shot-blocker.
However, Florida still boasts plenty on the front line. Seniors Patric Young and Will Yeguete both return, and transfers Damontre Harris (South Carolina) and Dorian Finney-Smith (Virginia Tech) both become eligible after sitting out last season.
"They're loaded," Walker said of the Gators. "Whatever role Coach Donovan wants to use me, I'm good with it. I just want to get there and play college basketball."