The Brewers selected Singleton's contract from Triple-A Nashville on Saturday.
With Darin Ruf (knee) headed to the 10-day injured list, Singleton will play in the majors for the first time since 2015 and serve as Milwaukee's backup first baseman. Singleton is slashing .258/.384/.483 with 10 homers and 29 RBI through 216 plate appearances with Nashville, but he likely won't make a big enough impact in Milwaukee to become a fantasy asset.