Littell was promoted to Triple-A Rochester on Friday.
Littell had an ugly 5.87 ERA through five starts at Double-A Chattanooga, but the Twins were clearly impressed by his underlying numbers. He struck out an impressive 31.7 percent of batters while walking just 6.9 percent, good for a 2.59 xFIP. Littell is on the 40-man roster, so if he continues his strong performance at the Triple-A level he could earn some big-league innings by the end of the season.