A rugged, sidearming sinkerballer, Aker relieved in all 495 of his ML games, saving 123. The nickname “Chief” refers to his Potowatomie Indian ancestry, fierce presence, and effectiveness. He was AL Fireman of the Year with the 1966 A’s, going 8-4 with a 1.99 ERA and 32 saves – a ML record until 1970. In August 1967, the Kansas City players, with Aker as their representative, became embroiled in a feud with owner Charley Finley. Having enraged Finley, Aker found himself pitching less and less. He was chosen by the Pilots in the 1968 expansion draft and was soon traded to New York. As a Yankee, he led the staff in saves in 1969 and recorded a 2.06 ERA in both 1969 and 1970, despite undergoing career-threatening spinal surgery over the intervening winter. He pitched with pain the rest of his career. When the Yankees acquired Sparky Lyle in 1972, Aker was dealt to the Cubs, and led their bullpen in saves and wins. He later became a successful minor league manager and Cleveland’s pitching coach.