The former American League MVP and Cy Young winner is trying to work his way back into the Tigers' rotation from a right triceps injury he sustained in spring training.
The Tigers have not announced whether Verlander will continue his rehab or now join the major league team.
"This whole time has been step-by-step, day-by-day, so I think the first thing is to see how I respond to pitching today and how I feel the next couple of days," Verlander said. "The hardest part is not being out there with my teammates."
Verlander gave up six hits, walked two and struck out three for the Mud Hens against Indianapolis, Pittsburgh's top minor league club.
"No issues with where I was injured, so that's obviously the most important thing coming away from today. But I would like to play a little more consistent in the strike zone," Verlander said. "It wasn't quite as good as I would like. A lot of 3-2 counts, extra pitches that were unnecessary."
Verlander was on a restricted pitch count of 80-85 pitches by the Tigers' staff in this International League start. He threw a total of 79, and reached 95 mph on two of his strikeouts.
Verlander threw 20 pitches in the first inning, striking out one. He threw 36 pitches in the second and faced a full count against four straight batters, walking two.
"I got my pitch count up and it felt all right. I just wasn't able to quite execute the pitch to put the (batter) away," Verlander said. "(My struggles) were just more mechanical, the inconsistencies throughout the mechanics."
Verlander didn't begin a throwing program until May 6. Prior to Sunday's start, Verlander had thrown two simulated games and multiple bullpens since the regular season began.
Verlander threw 4 1/3 innings in a simulated game Tuesday night before the Tigers played Oakland.
Despite displeasure with his inconsistencies, Verlander was pleased to be in a real game-situation against an unfamiliar opponent after almost a month of pitching exercises with Tigers' personnel.
"It's a little bit different with another team in the batter's box and you're not pitching against your own guys," Verlander said. "Obviously you never want to go on a rehab assignment, that means you got hurt. But, It was good to be in those situations."