Hellweg took a no-decision after throwing five innings against the Cardinals on Friday, allowing two earned runs on seven hits, while walking five and striking out one. He threw 97 pitches -- 49 of them strikes.
Roenicke said Hellweg's most recent start was promising enough to want to see more.
"We want to see again if he can bounce back and do it again," Roenicke said. "And when I say do it again, I know he threw a lot of pitches, I know he walked people, but I also know he only gave up a couple runs against a good team. So we've definitely got to see him again."
Hellweg's transition to the Majors has been shaky this season. The right-hander is 1-4 with a 7.43 ERA in six starts and a relief appearance. Roenicke said the biggest key is control for Hellweg, who has walked 22 batters and hit six more in 26 2/3 innings with Milwaukee.
"It just gets to where he throws some nice pitches and all of a sudden four bad ones and a walk," Roenicke said. "He's got to be able to not just pitch them on one side of the plate, but he's got to be able to pitch both sides of the plate to make sure he can get left-handers and right-handers out.
"I see a lot of progress. You guys don't see as much as I do, but I do."
Kevin Massoth is an associate reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.