Indianapolis Colts Coach Chuck Pagano was diagnosed with acute promyelocytic leukemia and is in isolation at a hospital, a source told The Indianapolis Star. Pagano, 52, will be hospitalized for about six weeks of treatment, the newspaper reported Monday. The first-year head coach had been feeling fatigued in recent weeks and underwent blood tests during the team\'s bye week, the Star said. A top Colts official acknowledged the coach\'s illness is serious but said, \"We\'re very optimistic about his recovery,\" the report said. The American Cancer Society website said 80 to 90 percent of patients with acute promyelocytic leukemia go into remission with early treatment -- important \"because patients with APL may develop serious blood-clotting or bleeding problems.\" Offensive coordinator Bruce Arians will coach the team in Pagano\'s absence, the Star report said.