Nix hit .133 in 34 games this season with the Pirates and Philadelphia Phillies. He is a career .214 hitter in seven big league seasons. He's also played for Colorado, New York Yankees, Chicago White Sox, Cleveland and Toronto.
The Royals also activated left-handed pitcher Scott Downs, who had been on the disabled list with a stiff neck. The team also optioned right-handed pitcher Liam Hendriks to Double-A Northwest Arkansas. Hendriks held Minnesota to one run and four hits over seven innings in a no-decision spot start Wednesday in his Kansas City debut.
The Royals recalled right-hander Michael Mariot, who had been on the disabled list at Triple-A Omaha, and put him on the 60-day disabled list to make room for Nix on the 40-man major league roster.
The Royals will have to make a corresponding move to add Nix to the 25-man roster when he reports.