By London correspondent Tony Hughes

Arsenal defender Per Mertesacker could be out for up to five months with a knee injury, according to Sky Sports.

The broadcaster claimed on their website on Tuesday morning that the Gunners are yet to confirm the news but will make an announcement about the centre-back in the next 48 hours.

Mertesacker suffered the knee problem during Friday night’s friendly against Lens and was left out of Arsenal’s pre-season tour of the United States.

Arsenal announced on their official Twitter account on Monday that Mertesacker had sustained a knee problem during Friday night’s friendly against Lens and would not be a part of the squad that travels on their pre-season tour of the USA.

The Londoners did not disclose any further details about the extent of the Mertesacker injury.

But Kike Marin, a senior correspondent and columnist for Spain’s leading online newspaper El Confidencial, revealed on his personal Twitter account on Monday night the German defender is facing a lengthy absence in what would be a shattering blow for the Gunners.

The report by Sky Sports, and news of an imminent announcement by Arsenal, suggests that Mertesacker will now become the latest in a series of Gunners players to have suffered serious pre-season injuries in recent years.

Jack Wilshere fractured his shin early last August and missed most of the subsequent campaign through injury.

The potential long-term absence of the former Germany international could mean Arsene Wenger having to dip into the transfer market to buy a replacement centre-back.

Mertesacker was lined up to be appointed the new captain this season following Mikel Arteta’s retirement.

The 31-year-old was pushed closely by Brazilian Gabriel Paulista in the battle to partner Laurent Koscielny at the heart of the defence last season but ended the campaign in the team.

The 2014 World Cup winner has made 207 appearances in all competitions since joining Arsenal in 2011 and his experience will be sorely missed.

The opening Premier League match against rivals Liverpool will be made even harder as five other senior stars are set to miss the clash, with Alexis Sanchez struggling with an injury according to the Mail Online.

In other Arsenal team news, a number of senior Gunners players are in doubt for the start of the upcoming campaign.