Houser, 23, ranks 17th on MLBPipeline.com's current list of the top Brewers prospects. The Brewers acquired him from the Astros last July 30 along with three other top prospects -- pitcher Josh Hader and outfielders Brett Phillips and Domingo Santana -- for Carlos Gomez and Mike Fiers.
The Brewers did not make any announcement of the surgery, though Houser is on their 40-man roster. It was reported by the Milwaukee Journal Sentinel and subsequently confirmed by farm director Tom Flanagan.
Houser posted a statement on Twitter saying the surgery repaired a "significant" partial tear to his ulnar collateral ligament.
"This is just a bump in the road that I will work hard to overcome and come back stronger from," he wrote. "It's a long rehab process and I'm ready to get to work so I can get back to competing and helping the Brew Crew wherever I can in the future."
Houser becomes the third member of Milwaukee's Top 30 Prospects list rehabbing from Tommy John surgery. Left-hander Nathan Kirby (No. 16 on the list) had it in September, just a few weeks after right-hander Taylor Williams (No. 22). The Brewers are hopeful that both will be participants in the fall instructional league.
"You realize injuries are part of it and you feel bad when it happens," Flanagan told the Journal Sentinel. "But at the same time, we know it's a surgery that has a very high success rate, and we're confident in our people to rehab Adrian and in Adrian to give the effort he's going to need."
Houser was 3-7 with a 5.25 ERA in 13 starts for Double-A Biloxi this season, but he was pitching well before the injury occurred. He had a 2.35 ERA in four starts in June.
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.