The D-backs are hoping to get him some appearances out of the bullpen in September.
"He threw great," Gibson said. "I got a good report on him. His velocity was up last night. He's feeling much more comfortable."
• Chase Anderson, Cliff Pennington, Xavier Paul and Jordan Pacheco visited patients at the Walter Reed National Military Medical Center on Wednesday morning.
• Outfielder A.J. Pollock, who is trying to return from a fractured right hand, is starting to progress again. Pollock suffered a setback when he was hit by a pitch on the hand while in the Arizona League.
"He's getting closer," Gibson said. "I haven't got a first date on when he's going to start playing again. He's close to getting in games again."
• Outfielder Cody Ross (left calf strain) is still not able to run using his full body weight. Ross is currently using an anti-gravity treadmill that allows a person to offload some of their body weight.
"He got set back when he tried to push it, and I don't think he's that close to playing yet," Gibson said. "But he's doing all the activities that he can."
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.