Castillo allowed two hits and issued two walks while striking out six batters over four scoreless innings in a no-decision against the Athletics on Monday.
After struggling mightily as a traditional starter this season, Castillo was deployed out of the bullpen for the first time in his career in his previous appearance May 19. The veteran righty was then moved back into a starting role Monday, but the plan all along was to pair him with Bryce Miller. Castillo ended up thriving with that setup, holding the A's to just two hits while racking up 12 whiffs and six punchouts over four frames. He was pulled after 68 pitches in favor of Miller, who fared well himself in closing out the contest by giving up two runs over five innings. It remains to be seen how Seattle will use Castillo going forward, but he made a case to remain a starter -- at least as part of a tandem -- with his performance Monday. Of course, it will dampen his fantasy value considerably if he's limited to fewer than five innings and 70 pitches as he was against the A's.