Gray was placed on the 15-day DL Sunday due to a strained right trapezius.
Gray had yet another shaky outing Friday, allowing four earned runs on six hits and four walks to bring his ERA up to 6.19 on the year. After opening the season with four straight quality starts, Gray has been unable to return to early-season form, but it now appears that an injury may have been in play. The Oakland ace will be given a couple weeks on the shelf to heal his ailing back, while the team will recall lefty Daniel Coulombe to take his spot on the roster. Gray had been scheduled to make his next start Wednesday in Seattle, but the A's have yet to announce an official replacement option.