Having 13 pitchers is generally one more than teams like to carry, but with their starters having averaged just five innings per start this year, the team has needed the extra arm in the bullpen.
However, the D-backs no longer want to leave themselves short on bench players, so there will be some roster juggling ahead.
Ross has been out since last August, when he suffered a fractured and dislocated right hip while running to first base.
Steve Gilbert is a reporter for MLB.com. Read his blog, Inside the D-backs, and follow him on Twitter @dbackswriter. This story was not subject to the approval of Major League Baseball or its clubs.