Gray (forearm) was placed on the 15-day DL on Sunday.
Gray's disastrous season took yet another turn for the worse in Saturday's start against the Cubs, during which the right-hander gave up two runs over five innings before departing after 72 pitches with right extensor muscle soreness. It's not clear if the Athletics conducted an MRI that determined Gray was dealing with anything more severe than soreness, but given the team's low place in the standings, they won't take any chances with their presumptive ace. The A's purchased the contract of Chris Smith from Triple-A Nashville to fill out their pitching ranks while Gray is sidelined.