Arsenal have confirmed Per Mertesacker has been ruled out of the trip to the United States with a knee problem.
The German managed to play against Lens on Friday but the Gunners have now revealed he is suffering with a knee injury and will stay back at London Colney for treatment.
The full extent of the damage has yet to be revealed and the Gunners are taking no chances, with the new Premier League season fast approaching.
The Gunners also confirmed on their website: “With Laurent Koscielny resting after Euro 2016 and Gabriel suffering from tonsillitis, Calum Chambers is our most experienced centre back on tour.
“Our 23-man squad includes plenty of younger players, including Jeff Reine-Adelaide, Chris Willock and Gedion Zelalem. Santi Cazorla did not play against Lens but could face MLS All-Stars and Chivas.”
New signings Granit Xhaka and Rob Holding are both in the squad.