Manager Scott Servais said Thursday that he expects Castillo (shoulder) to return after missing the minimum of 15 days, Shannon Drayer of 710 ESPN Seattle reports.

EDGE Analysis

Castillo landed on the 15-day IL with right shoulder inflammation Thursday, but the issue doesn't seem to be a significant concern. Servais said the right-hander would likely be able to return after 5-6 days, but the Mariners elected to place him on the IL to avoid a shorthanded bullpen. Andres Munoz and Matt Festa will likely see increased high-leverage chances ahead of closer Paul Sewald while Castillo is sidelined.