 In the 1967 NFL championship, the "Ice Bowl" played on New Year's Eve, 1967, Hayes was alleged to have inadvertently disclosed whether the upcoming play was a pass or run because on running plays he kept his hands inside his pants to keep them warm and the Green Bay defense knew they didn't need to cover him.On July 17, 1975, he was traded to the San Francisco 49ers in exchange for a third round draft choice (#73-Duke Fergerson).In 1975 with the San Francisco 49ers, Hayes teamed up with Gene Washington in the starting lineup.