Borussia Dortmund have already held initial talks with the representatives of Arsenal target Abdou Diallo.
The Ruhr giants expect to sell experienced defender Sokratis Papastathopoulos, who has refused to sign an extension to a contract which is due to expire in the summer of 2019.
Dortmund have zeroed in on Mainz defender Diallo as the perfect replacement for Sokratis.
Arsenal are also firm fans of the former Monaco man, who has impressed following a solid first season in the Bundesliga with Mainz.
Mainz have steadfastly refused to consider selling a player they paid Monaco €5m to sign just last summer, but Dortmund do not appear to be taking no for an answer from their fellow Bundesliga outfit.
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And according to German outlet Fussball Transfers, Dortmund have already been in contact with Diallo's representatives.
It remains to be seen if Mainz will change their stance on Diallo, but Dortmund have also been linked with Wolfsburg youngster Felix Uduokhai as another option.
