Mustafi and Frenchman Laurent Koscielny appear to be striking up a formidable partnership in the centre of defence, meaning it might be difficult for club captain Mertesacker to get back into the side when he returns.
Subsequently, the German is not sure whether his future remains at the Emirates, especially given that his contract is due for renewal at the end of the season.
He told kicker: ‘I am person who likes to create options for himself. Of course, I ask myself what would make sense if things were to end at Arsenal.’
‘Where can I be of any help? What do I want? Could I maybe return to Germany?
‘I look at the perspectives for me and my family, and I think that I’ll intensify those thoughts from January on. That’s also the time when you can listen to other things [offers] when your contract is expiring.’
Mertesacker’s comments may have arisen from the interest shown by his former club Hannover, who are keen to bring him back to the German side ten years after he left for Werder Bremen.