Arsenal boss Mikel Arteta faces a defensive headache for Thursday's Europa League tie against Dundalk with David Luiz missing through injury.
Luiz's absence leaves the Gunners boss with the option of Shkodran Mustafi and Gabriel Magalhaes as the only two fit central defenders.
Mustafi, 28, replaced Luiz during Sunday's Premier League defeat by Leicester City.
Arsenal host Dundalk at Emirates Stadium in Group B at 20:00 GMT.
German World Cup winner Mustafi, who is returning from a hamstring injury sustained in the FA Cup semi-final on 18 July, says no talks have begun in regards to extending his contract with the club.