Ebert posted a progress letter on his Chicago Sun-Times Web site, telling fans he has been bedridden since July 1 and is eager to return to work.
"I have always believed in full disclosure," he wrote. "When I announced that I had a recurrence of salivary cancer that required surgery, I had no idea when I went into the hospital on June 16 that I would still be here on (Aug.) 16."
But Ebert, 64, said doctors "are enthusiastically optimistic about my recovery."
"I am a lucky man," he added.
While he recovers, guest critics have joined Richard Roeper on "Ebert & Roeper." The latest additions include comic actor Fred Willard, screenwriter and novelist John Ridley, actress Aisha Tyler, entertainment reporter Toni Senecal of WNYW-TV in New York and Chicago Tribune movie critic Michael Phillips.