The organization had decided to shut down Bauer for a couple of weeks in order to give him a breather during his first full professional season.
Bauer made four starts for the D-backs after being called up on June 28 and went 1-2 with a 6.06 ERA. After his demotion last month, he made one start before being shut down.
On Monday he allowed just five hits and walked two while striking out five. He threw 80 pitches, 53 for strikes.
Being more efficient with his pitches is something the D-backs have preached to him.
"He came out and tried to throw strikes last night," manager Kirk Gibson said. "You just have to do it. You can't nibble it. Guys aren't going to keep swinging at balls. You have to make quality pitches, you have to have some movement on it and you can't overthrow pitches -- if you do, you're going to get in trouble. You have to learn to trust your stuff."
Bauer's velocity during the outing ranged from 91 mph to 96 mph, faster than what he showed during his time in the big leagues.