Ballas moves from relegated Dynamo Dresden, where he had been captain, and is reunited with former Dresden centre defensive partner Sören Gonther, who made the same move last season.
The 27-year-old spent four years with Aue’s bitter Saxony rivals, and prior to that was with Hannover and FSV Frankfurt.
He played 30 games for them last season and acted as captain under Markus Kauczinski in the absence of Marco Hartmann. He left the club after their relegation was confirmed as part of a mass cull with his contract invalid for the third tier.
Left-back Bussmann joins from EA Guingamp, however the Frenchman previously had spells in Germany with both Freiburg and Mainz, with 28 Bundesliga appearances to his name for the latter, as well as five Europa League games.
Meanwhile, Strauß, whose contract had ended at the end of June, has signed on for another year, with an option for a further 12 months. He joined from RB Leipzig II in 2017 and has made a total of 41 appearances for Aue so far.
The club returned to training on Saturday, with three players returning from loan moves – Sascha Härtel, Paul Horschig and Niklas Jeck – all there. Pascal Testroet was missing however. The striker has recently undergone a knee operation.
Header image source: FC Erzgebirge Aue.