Drafted as a
shortstop, Mulliniks made his major league debut in for the
California Angels,
batting .269 in 78 games. He saw limited playing time over the following years with the California Angels until and with the
Kansas City Royals in and . He had been traded along with
Willie Aikens from the Angels to the Royals for
Al Cowens and
Todd Cruz at the
Winter Meetings in
Toronto on December 6, 1979, with
Craig Eaton being sent to California to complete the transaction four months later on April 1, 1980. Mulliniks' luck changed when he was traded to the
Toronto Blue Jays, just before the start of the season. He was converted to
third base and
platooned at that position as the left handed hitting half with
Garth Iorg until Iorg's retirement after the
1987 season. He appeared in over 100 games each year through . He batted over .300 three times (, and ) and demonstrated great patience at the plate, regularly posting
on-base percentages near .400. In 1984,
Sports Illustrated named him to their "Dream Team" as a utility infielder. In 1992, Mulliniks played only three regular season games for the Blue Jays, and none in the Blue Jays' postseason run to their
first World Series, as he struggled with injuries. Mulliniks retired after the season having compiled a .272 career batting average, 73
home runs, 435
RBI, and 445
runs. He holds the Blue Jays franchise single season fielding percentage record for third basemen (.975) and the franchise record for most pinch hits (59). ==Post-playing career==