Manager Mike Matheny said Wednesday that Keller will move to the bullpen, Joel Goldberg of Bally Sports Kansas City reports.
Keller has served exclusively as a starter in the majors over the last four seasons but has struggled since the All-Star break in 2022. Over his five starts to begin the second half, he's posted an 8.76 ERA and 2.07 WHIP in 24.2 innings. He had lined up to start Thursday's road matchup against the Rays, and the Royals haven't announced who will take his place in the rotation. However, Keller will attempt to sort things out as a relief option.