 McKay signed as an amateur free agent with the Minnesota Twins on June 20, 1971, and worked his way through the Twins minor league organization.McKay made his Major League debut on August 22, 1975, hitting a home run in his first at-bat against Vern Ruhle of the Detroit Tigers in an 8-4 victory.McKay appeared in 35 games with the Twins, hitting .256 with two home runs and 16 runs batted in.