Borussia Dortmund’s coaching staff have been baffled by Pierre-Emerick Aubameyang's recent behaviour, amid links with a move to Arsenal.
The striker was dropped for last weekend's Bundesliga clash with Wolfsburg for skipping a key team meeting.
It was the second time this season he has been banned by his club for "disciplinary reasons".
The 28-year-old is a reported target for Arsenal as a potential replacement for Alexis Sanchez, who is expected to depart the Emirates Stadium this month.
Aubameyang is one of the most coveted strikers in Europe having scored 31 Bundesliga goals last season and boasting 13 in 15 games so far this term.