Arsenal defender Per Mertesacker will be out for "a few months" with a knee injury, Arsene Wenger has confirmed.
The centre-back was injured during Friday night's friendly against Lens and was left out of Arsenal's pre-season tour of the United States amid reports he could miss five months.
And Wenger confirmed the extent of the injury in his first US press conference as the Gunners arrived for their two-match schedule.
Mertesacker, who was Arsenal's vice-captain last season, was favourite to be named new club captain at the Emirates following Mikel Arteta's departure to Manchester City in the summer.
Arsene Wenger's side have problems at centre-back with Gabriel Paulista struggling with tonsillitis and Laurent Koscielny allowed an extended break after reaching the final of Euro 2016 with France.
That leaves Calum Chambers as Arsenal's only fit senior central defender but new signing Rob Holding could partner his England U21 colleague in the US.
Arsenal play an MLS All-Star team on Friday and finish their tour against Chivas on Monday.