The infielder played nine rehab games between the Rookie League AZL D-backs and Reno, hitting .406 (13-for-32) with a .950 OPS.
"Obviously, you want to be swinging the bat well," Pennington said. "Felt good the 10, 12 days I was playing with those guys."
Pennington was in the starting lineup for his first day back, playing third base -- a position he has played only 11 games at in the Major Leagues.
"I just want to play," he said. "If Miggy goes down, I'll put the catcher's gear on.
"It's definitely a new position. There's no denying that. … But at the same time, it's still a ground ball."
Schultz, meanwhile, is making the trip back to Reno for the second time this year. Schultz has pitched four games in two different stints with the D-backs.
After pitching one game with the team in Australia, he made three appearances from July 29-Aug. 5. In that stretch, he was 0-1 with a 9.00 ERA.
"I was … trying to overpower people," Schultz said. "It may be a power fastball, power slider, whatever. But if it's not commanded the way you need it to be, it doesn't matter here.
"You throw 97 here, it's good, but it's not like it's completely unique. You do it in the Minor Leagues, you can get away with it a little bit more."
Manager Kirk Gibson said Schultz will go back to the starting rotation in Triple-A. In 21 starts with Reno this season, Schultz is 8-7 with a 5.75 ERA.
"I think they're going to work on changing his delivery a little bit, trying to keep him closed a little longer as well," Gibson said.