The Brewers claimed Rowen, a 27-year-old sidearmer, off waivers from the Blue Jays on Aug. 4. He posted a 1.69 ERA and 12 strikeouts over 10 2/3 innings with Colorado Springs, lowering his ERA to 2.33 over 45 appearances in 2016 for Toronto's and Milwaukee's top affiliates.
"It's good to be here," Rowen said. "I'm excited to be here in this clubhouse.
"The key for me has just been going out there and going with my game plan that I put together before the game, watching the hitters. Going out there and throwing fastballs, that's what I do."
Rowen views the callup as an audition for next season.
"I go into it and have a clear mindset," Rowen said. "Hopefully go out there on the mound and set up for next year, but just go out there anytime I can and help this team win."
"He is the ultimate submarine pitcher," Brewers manager Craig Counsell said. "This is a guy that's really from a different arm angle and he's unique, that's what makes him different. Hitters don't like different, he is something very different and he's going to pitch and we'll see how he does."
The Brewers are expected to promote additional players, including an extra catcher, after Minor League regular seasons end Monday.
Adam McCalvy has covered the Brewers for MLB.com since 2001. Follow him on Twitter @AdamMcCalvy, like him on Facebook and listen to his podcast. This story was not subject to the approval of Major League Baseball or its clubs.