Gabon striker Pierre-Emerick Aubameyang sat out his side’s Champions League clash with Sporting CP on Wednesday with the reasons remaining unclear.

Borussia Dortmund edged their Portuguese counterparts 1-0 courtesy of an Adrian Ramos strike in the first half, but it was Aubameyang’s absence that grabbed the headlines.

‘It was very difficult to do without him,’ coach Thomas Tuchel said after the match.

‘But it was that I had no choice. The decision was made yesterday [Tuesday] afternoon. In the next game, he will be back.

‘But, internal reasons means internal. I do not account for speculation.’

Aubameyang’s suspension has increased talk that the striker has fallen out with Tuchel and could be headed for a January exit.

Aubameyang will return to the squad for Saturday’s Bundesliga encounter with Hamburg.