Local Valenica paper Super Deporte have reported the German international could make a surprise move back to Germany.
The German defender has struck up a strong partnership with Nicolás Otamendi this season, while Valencia have already rejected advances from English side Manchester United. Now Borussia Dortmund are interested in Mustafi and are looking to take him to the Bundesliga for next season. As of now, there has been no official talks between the two clubs, but it seems Jürgen Klopp is keen to add the 2014 World Cup winner.
The good news for Valencia is that the talented defender wouldn't be allowed to leave for a cut price deal, as his current buy out clause is set at €50 million. The figure was inserted to the five-year contract he signed in August 2014, when he arrived at Mestalla from Italian outfit Sampdoria. Super Deporte also maintain that the Champions League chasers have absolutely no intention to sell the defender, and only a significant offer from Dortmund would be able to make them even consider a deal.