"He needs to work on location with his fastball; that's the main thing," D-backs manager Chip Hale said. "He needs to work on his breaking ball. His changeup and sinkers are very good pitches, but his sinker, he needs to be able to locate it."
The D-backs will need to find somebody else to start on Saturday against the Rockies now that they have only four starters on their roster. Hale said long reliever Josh Collmenter could be an option. The fifth spot in the rotation will go to Patrick Corbin when he returns next week in Texas.
Stites began the season on the 15-day disabled list with right elbow inflammation and was not reinstated until June 1, when he was optioned to Reno. He recorded three saves and allowed three runs in nine innings during nine appearances with the Aces.
"It took about three, four maybe, appearances for me to kind of get my groove, get comfortable, get going out there," Stites said. "I feel like I'm more focused, more dialed in on the pitch, instead of just kind of going out there reckless."
Jake Rill is an associate reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.