The Royals optioned Speier to Triple-A Omaha following Sunday's 4-2 loss to the Blue Jays.
Speier is one of 10 players who will come off the 26-man active roster with Kansas City needing to clear room for the 10 players returning from the restricted list ahead of the team's next game Friday against the Rays. The 27-year-old lefty reliever went unused in Sunday's loss after being called up from Triple-A prior to the contest.