Mariners' Jhonathan Diaz: Optioned to Triple-A

The Mariners optioned Diaz to Triple-A Tacoma on Wednesday.

Diaz made his one appearance for Seattle on Tuesday and allowed no runs on one hit with a strikeout in 1.1 innings. The southpaw has made the bulk of his appearances for Tacoma as a starter and figured to get a shot at securing a rotation spot in place of the injured George Kirby (shoulder), but he'll instead return to the minors after a relief appearance. Luis F. Castillo is expected to be promoted from Triple-A Tacoma to make his first career start Friday.