With Reno this year, Spruill was 3-7 with one save and a 6.04 ERA in 28 games (11 starts).
This is Spruill's third stint with the D-backs this year. He started the second game of a doubleheader May 25 and allowed three runs in 5 1/3 innings.
Then he made a relief appearance June 25 against the Indians and allowed two runs over four innings.
It didn't take long for Spruill to see action as he was summoned to replace an ineffective Wade Miley on Tuesday and he held the Giants to two runs (one earned) over four innings.
Steve Gilbert is a reporter for MLB.com. Read his blog, Inside the D-backs, and follow him on Twitter @SteveGilbertMLB. This story was not subject to the approval of Major League Baseball or its clubs.