Fotheringham left Freiburg after failing to make a single start last season for the German side.
"It doesn't matter what league you are in, if you are not playing, there's no point," he said last month. "Everything else about Freiburg has been perfect for me. But I've told the coach, Volker Finke, I'm unhappy at not playing and that I want to leave."
Fotheringham, who made just three appearances for Celtic, had two seasons with Dundee before leaving for Freiburg last summer.