Pitching against the Oklahoma RedHawks in his home state, Penny threw 67 pitches, 50 of those for strikes, and struck out four batters while walking one. He threw as hard as 97 mph and left with Las Vegas trailing 2-1.
The 30-year-old right-hander is set to rejoin the Dodgers on Monday in St. Louis, and is tentatively scheduled to start for Los Angeles on Friday against the San Francisco Giants.
After recording 16 wins in each of the past two years and finishing third in the voting for last year's National League Cy Young Award, Penny has struggled this season.
He was 5-9 with a 5.88 ERA in 15 starts for the Dodgers before going on the disabled list, retroactive to June 15, with shoulder tendinitis and bursitis. An MRI exam revealed no structural damage.
Last Saturday, he threw 52 pitches to teammates in a three-inning simulated game. The Dodgers opted to follow that with a bullpen session Monday, followed by a single minor league rehab start with Las Vegas in the Pacific Coast League.
In 102-degree heat, Penny started quickly, retiring the first five Oklahoma batters he faced before allowing a second-inning single to John Mayberry. Through three innings, Penny had thrown 37 pitches, less than half of the planned 75.
Penny ran into trouble in the fourth, giving up a double to Nate Gold, a run-scoring single to Ryan Roberts and an RBI double to Mayberry to start the inning. Penny reached 96 mph on the radar gun close to the end of his stint.