Manager Ned Yost announced opening starters Saturday and says Wade Davis is no longer a candidate for a spot in the rotation.
Davis made 24 starts before being sent to the bullpen last season. Yost says the decision on Davis was made after Luke Hochevar was lost for the season to reconstructive elbow surgery.
Yost says left-hander Danny Duffy and rookie right-hander Yordano Ventura are the remaining candidates to fill out the rotation.
Jeremy Guthrie, who led the Royals with 15 victories last year, will start the home opener on April 4 against the Chicago White Sox.
Shields, who started the opener last season, was 13-9 with a 3.15 ERA last.