During pre-season training in the summer of 2012, Hasenhüttl contracted a Hantavirus infection, but returned to work three weeks into the 2012–13 season. Hasenhüttl had switched from a 4–4–2 to a 4–5–1 formation, to facilitate a fast, counter-attacking game, with success – by the winter break, Aalen were in fifth place. The team finished the season in ninth place, the highest of the newly promoted teams.