Per Mertesacker has been ruled out with a knee injury, leaving Arsenal with Calum Chambers and Rob Holding in central defence.
The German had played in last week’s friendly against French side RC Lens, but has been sent home from the club’s US training camp after suffering a knee injury.
Arsenal did not disclose a potential return date for the central defender, and merely described his injury as a “knee problem”.
However, Spanish journalist Kike Marin reports that he could face a five-month spell on the sidelines, returning as late as 2017.
— Arsenal FC (@Arsenal) July 25, 2016
The Daily Mirror offer a slightly more kind prognosis, claiming the 31-year-old ‘will instead remain at the London Colney training base and continue his rehabilitation, with the intention of meeting up with the rest of the squad in Sweden’.
Mertesacker being sidelined does leave Arsenal with Chambers as their most senior recognised centre-half, with Laurent Koscielny absent from pre-season after Euro 2016, and Gabriel suffering from tonsilitis.
Holding, signed from Bolton for £2m, is also expected to feature more heavily in pre-season as a result, while Nacho Monreal and youth midfielder Krystian Bielik both have some experience in the role.