According to sporting director Michael Zorc, Kagawa, 25, is still set to make his Dortmund return on Saturday despite limping out of training.
Zorc said it was precautionary for the former Manchester United man to leave training as coach Jurgen Klopp looks to deal with the absence of the injured Marco Reus.
"It was a precautionary measure. We assume that he can play Saturday," Zorc told Bild.
Speaking before training, Klopp – whose side have a win and a loss early in the season – welcomed back the Japan international.
Klopp said he could almost see everything he did when Kagawa left the Bundesliga giants in June 2012.
"We just trained together for four or five days but we have to perform against Freiburg," he said.
"I saw most of the things that were there when he left us, but not everything.
"But of course he's now two years older and more experienced.
"He speaks English now and still a bit German which will improve in the next months because he has a much better basis now.
"It's very enjoyable to have him back around and in our dressing room."
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