In 1972, while playing winter ball in Puerto Rico, Walker along with several other players helped Roberto Clemente load a plane carrying relief supplies to survivors of the Nicaragua earthquake after Christmas. He offered to accompany Clemente on the trip to the Central American nation, but the plane was full and Clemente told him to stay behind and enjoy his New Year's Eve. A few hours later, Walker returned to his condo and saw the news reports that Clemente's plane had crashed off the coast of Isla Verde, Puerto Rico.