Arsenal manager Arsene Wenger has confirmed that midfielder Jack Wilshere will be out for weeks after suffering a hairline fracture to his right ankle.
The Englishman joins striker Danny Welbeck and midfielder Tomas Rosicky on the sidelines with Chile's Alexis Sanchez not match fit ahead of this weekend's Premier League opener.
The Gunners host West Ham United on Sunday afternoon and will face Crystal Palace away from home next week.
"The information you have heard about Jack Wilshere is right," Wenger told the club's official website.
"I had a bad surprise because it is a hairline crack in his fibula that makes him a few weeks out.
"There is minimal damage apart from the bone damage - there is no damage at all apart from that. It was a collision in training and it was all completely accidental.
"We have [Danny] Welbeck on a progressive recovery and [Tomas] Rosicky on a progressive recovery.
"He [Welbeck] is not too far away, but he is not ready for Sunday.
"Alexis [Sanchez] is back in training but I don't think he will be involved on Sunday, it is a bit early maybe. We have to decide that at the end of the week, but I don't think he will be involved.
"He came back in good fitness shape so that is quite positive, but I am not surprised by that because I can't imagine him lying around for four weeks and doing nothing. That wouldn't be him."