The Czech international made his first appearance in seven months for the Gunners last weekend as a substitute in their 2-1 FA Cup victory over Burnley as he looked to put his past injury woes behind him.
Yet a thigh injury picked up during the game will see the 35-year-old spend even more time on the side-lines, and with his contract at Arsenal up in June, last weekend’s cameo could have been his final few minutes ever in a Gunners’ shirt.
Arsene Wenger delivered the bad news at a press conference on Friday, revealing that all at the London club are shocked.
“How long will it take? Two to three months,” Wenger said. “At the moment we are all shocked and he’s the most shocked.
“His injury is quite a serious muscle injury. The good news is that apparently he will not need surgery. It’s a partial rupture.
“We have to be patient and hope that it was not his last game. I don’t want to be dramatic, he suffers enough at the moment. I’m more in a support attitude than dramatic.”
Arsenal, who now lie fourth in the Premier League standings, face Bournemouth in their next clash on Sunday.