The Red Sox issued a statement confirming the death of the son, who was 35, and who had led efforts to have his famous father's body preserved at a cryonics lab in Scottsdale, Ariz., setting off a family legal battle.
"On behalf of all of us with the Boston Red Sox, we extend our condolences to the John Henry Williams family," the team statement said. "Perhaps no person meant more to the history of the Boston Red Sox than did his father."
John Henry Williams, who played briefly in the minor leagues, was diagnosed with a form of leukemia last fall. He had been undergoing chemotherapy.
"It is particularly sad that leukemia claimed his life, for his father was a pioneer in the development of the Jimmy Fund, which has made such remarkable progress in the fight against cancer," the Red Sox statement said.
Ted Williams, one of baseball's legendary sluggers, died in 2002. A family dispute followed after his son had the body taken to the cryonics lab. The family settled the matter last year.