Hahn didn't disappoint, allowing one run on three hits over six innings as the Padres defeated the Braves, 5-2, at Turner Field.
Hahn, in his first Major League start since July 11, walked three and struck out four and lowered his ERA to 2.12 in his eighth big league start. He threw 88 pitches, 55 for strikes.
"I thought that his stuff was very comparable to where it was a few weeks ago," said Padres manager Bud Black.
The Padres were able to pull Hahn (6-2) with a four-run lead after six innings because they not only felt good about their bullpen, but because these are the types of situations they will likely face moving forward as they monitor the 24-year-old's innings.
Hahn has thrown a combined 87 innings this season between Double-A San Antonio and his time with the Padres, including two innings with San Antonio on Monday to keep his arm fresh.
Hahn totaled 69 frames last season in the Rays system, as that organization was bringing him back slow from 2010 Tommy John surgery. Black has said it is unlikely that Hahn doubles his innings output from a year ago.
"He's in a spot where he has somewhere between five and 10 starts left," Black said. "We're going to watch him every start."
"Right now, we're not going to slow him down. We're trying to win games. This is good development for him, trying to win games in the middle of summer, in the dog days."
What exactly are the Padres looking for in Hahn?
"You've got to look at how he's throwing the baseball, all the physical things you look for. ... His delivery, his stuff, whether he's throwing with a free and easy motion," Black said. "How is he feeling, how his stuff his, how is his velocity, how sharp his secondary pitches are from start to start."
"If his innings are stressful and if games are stressful, that will take a toll on him."
So far, so good for Hahn, who said Friday that he didn't pick up a baseball for five days during his break before joining San Antonio.
"I felt good. My fastball command was good," Hahn said.