Thornburg will join the starting rotation at Triple-A Colorado Springs, MLB.com's Adam McCalvy reports. Thornburg was off to a rough start, allowing 13 runs (six earned) in his first 9.2 innings of 2015. He'll now be stretched out as a starter, with the organization hoping this will help get the righty back on track. It seems likely Thornburg will be back with the Brewers at some point this season.