 McKay signed with the Oakland Athletics on April 4, 1980, and in 129 games with the Athletics, McKay hit .244 with one homer and 29 RBI as a utility infielder.He improved offensively in 1981, as McKay hit .263 with four home runs and 21 RBI in 79 games, helping Oakland reach the playoffs.In the 1981 American League Divisional Series, McKay hit .273 with a home run and an RBI as the Athletics defeated the Kansas City Royals to advance to the American League Championship Series.