Transfer market expert Emanuele Giulianelli says Valencia defender Shkodran Mustafi will join Arsenal this week.
The Germany international has already agreed personal terms over a move to the Emirates but the two clubs are yet to reach an agreement.
"Mustafi update: still bid no accepted, although personal terms agreed and player requested the move. Still expect to be done by end of week," Giulianelli wrote on Twitter.
The Gunners started the season with a home defeat at Liverpool and the defensive department was shaky in a number of occasions as they conceded four goals.
And manager Arsene Wenger desperately wants to add a new central defender before Saturday's away game at Leicester City.
Four days ago, the Frenchman thought his squad was well equipped to face Jurgen Klopp's men but he was clearly mistaken as Calum Chambers and Rob Holding struggled to cope with the pace and movement of the Liverpool strikers.
"Of course we lost basically three centre backs, because we have [lost] Mertesacker and Gabriel and Koscielny, who is not ready," he told reporters.
"Most of the time, the injuries happen in the same sector.
"But I believe we are equipped to do well and I’m confident we can do well. Transfer-wise, as soon as we do something, we will inform you."