The surgery set for Monday comes a week after Greens brother and girlfriend were killed in the accident in eastern Mississippi.
Kevin Richardson told The Associated Press Sunday that doctors had hoped Green could keep the leg, but there was too much damage. The 50-year-old Green hopes to someday make a return to the golf course with the help of a prosthetic limb.
William Y. Green, of Indiantown, Fla., and Jean Marie Hodgin, of Greensboro, N.C., were killed in the wreck.
Authorities say the right front tire on Ken Greens recreational vehicle blew out on Interstate 20 near Hickory, Miss. The RV went down a steep embankment and hit a tree.