“It's not been an easy situation for Koen. The transfer is a new prospect for him,” said Alexander Rosen, director of football at TSG. The 22-year-old Belgian broke his leg in a 1-1 draw with Hertha Berlin on 6th April 2014.
After successfully completing rehab, Casteels got some match practice with Hoffenheim's reserve team in the fourth tier of German football. The goalkeeper made a total of 39 Bundesliga and 32 Regionalliga appearances for TSG, and also featured in two DFB Cup games.