The Diamondbacks recalled Thomas from Triple-A Reno on Thursday, Alex Weiner of ArizonaSports.com reports.
Thomas was optioned to Triple-A in the middle of August, but landed on the 7-day injured list due to a right oblique strain a few days after. He was reinstated from the injured list Sept. 18 after missing a month of action. With his return to the big club, Yilber Diaz and Blake Walston were optioned to Triple-A Reno as part of a corresponding move.