Hall of Fame football coach Bill Walsh, who built an NFL dynasty with the San Francisco 49ers and revolutionized the sport with his West Coast offense, disclosed Friday that he has leukemia.

Stanford officials confirmed that Walsh, who served as the school's interim athletic director until July, has told friends and colleagues there that he has cancer.

"I'm positive, but not evangelistic," the 74-year-old Walsh told The (Santa Rosa) Press Democrat and The Sports Xchange Web sites. "I'm pragmatically doing everything my physicians recommend, and I'm working my way through it."

Walsh said the cancer first was diagnosed in 2004, but he feels better since a series of blood transfusions in the past month.

"The worst phase was three or four weeks ago. I've come back dramatically since, and I'm better," he said.

He said he was going public now, because word had begun to circulate.

A call to Walsh's home wasn't immediately returned to The Associated Press.

Walsh was 47 when he first became an NFL head coach, and he spent just 10 seasons on the sideline. But he left an indelible mark, winning three Super Bowls and turning the 49ers into the most successful team of the 1980s with his innovative offensive strategies and teaching techniques.

Few men did more to shape the look of football into the 21st century. His cerebral nature and often brilliant stratagems earned him the nickname "The Genius" well before his election to the Pro Football Hall of Fame in 1993.

Walsh went 102-63-1 with the 49ers, winning 10 of his 14 postseason games along with six division titles. He was named the NFL's coach of the year in 1981 and 1984.

Walsh twice served as the 49ers' general manager, and George Seifert led San Francisco to two more Super Bowl titles after Walsh departed. Walsh also coached Stanford during two terms over five seasons, and was the school's interim athletic director until Bob Bowlsby was hired in April.

"I always felt I'll accept my fate as it unfolds," Walsh said. "I have no regrets, and when it was life-threatening, I had a lot of considerations about my wife, Geri. It appears I've gone through that threshold and it may turn out OK, at least for a while."