Arsenal are upset with Hannover over their treatment of Takuma Asano.
The Mirror says Hannover are reportedly refusing to play on-loan forward Asano in a bid to avoid paying a buy-out clause, a decision that has angered Arsenal.
The 24-year-old linked up with the Bundesliga strugglers on a temporary basis at the beginning of the season.
It's been reported in Germany that if Asano plays one more game this season, the German side will be obliged to pay £2.6million to purchase him permanently from Arsenal.
Hannover have informed the Premier League club of their stance - and it's been met with frustration.