Mariners' Riley O'Brien: Outrighted to Triple-A

O'Brien cleared waivers and was outrighted to Triple-A Tacoma on Thursday.

O'Brien struck out one in a scoreless inning during his lone relief appearance for the Mariners in early May, but he was sent down May 8 and designated for assignment Friday. However, the right-hander will remain in Tacoma, where he's posted a 2.70 ERA and 1.60 WHIP in 10 innings over 10 relief appearances this year.