Castillo allowed five runs (four earned) on seven hits and struck out four without walking a batter over four innings of relief in Friday's 6-2 loss to the Red Sox.
Castillo wasn't tagged with the loss, as that went to Bryce Miller. The Mariners' offense didn't give much support to either pitcher, but Castillo didn't do his part to keep the game close after a four-run seventh inning. He has now allowed 11 runs (seven earned) across 15.1 innings in June. Both Castillo and Miller are expected to work in traditional starts at some point during the Mariners' six-game road trip next week.