Jon Lester is slated to return to the mound for the Red Sox on Monday, nearly a year after his rookie season was cut short when he was diagnosed with cancer. Lester was scheduled to replace Julian Tavarez for Monday's game at Cleveland, the 23-year-old left-hander's first major league appearance since he beat the Angels on Aug. 23 last year. The Red Sox said nine days later that he had a treatable form of lymphoma. "I don't think it really has sunken in yet, and I don't think it will sink in until tomorrow when I get on the mound," Lester said Sunday.