The move is related to an injury to leadoff man Maicer Izturis, who was scratched from Sunday's lineup with a strained left hamstring. Amarista was batting .455 with 16 RBIs in 14 games at Salt Lake. Willits, who began the season on the disabled list with a calf injury, was 0-for-7.
Izturis, who is listed as day to day, leads the Angels with a .338 batting average, which ranks 10th in the American League.
Mark Saxon covers the Angels for ESPNLosAngeles.com.