The 91-year-old Feller said Sunday he was feeling better and his prognosis was good. He was found to have acute myeloid leukemia in the past two weeks and spent two days at the Cleveland Clinic, followed by a week of outpatient care.
Feller produced a career record of 266-162 in 570 games in 18 seasons, all with Cleveland. He did not play from 1942-44 while he served in the Navy during World War II.
He was inducted into the Hall of Fame in 1962.