The Mariners optioned Bernardino to Triple-A Tacoma on Monday.
Bernardino was moved off the 26-man active roster to clear a spot for newly acquired right-hander Luis Castillo, who reported to the Mariners on Monday. A 30-year-old journeyman southpaw, Bernardino received his first call to the big leagues over the weekend after turning in an 0.79 ERA and striking out 17 over 11.1 innings at Tacoma. He made his MLB debut in Sunday's 3-2 loss to the Astros, taking the loss in the 10th inning after allowing an unearned run.