The Royals transferred McArthur (elbow) from the 15-day injured list to the 60-day IL on Sunday.
McArthur missed the entire 2025 season while completing his recovery from surgery to address an elbow fracture, and though he was considered healthy heading into spring training, he experienced a minor setback before the end of camp. The right-hander resumed throwing bullpen sessions just over a week ago, but he now won't be eligible to join the big-league staff until at least late May. The transaction frees up a 40-man roster spot for catcher Elias Diaz, who was promoted from Triple-A Omaha.