The Welshman is out for up to six weeks, while his English counterpart rolled his ankle against Tottenham and is joined by the centre-back in a race to be fit
Arsene Wenger faces a selection dilemma when Arsenal face Galatasaray in the Champions League on Wednesday.
Injuries to Aaron Ramsey, Mikel Arteta and Jack Wilshere have left the Premier League side short options as they look to bounce back from a 2-0 defeat to Borussia Dortmund in their first Group D encounter.
With Abou Diaby still early in his recovery from 18 months out, Wenger has hinted that Calum Chambers may be used in a midfield role ahead of Mathieu Flamini, while Tomas Rosicky could be called upon.
While Wenger is confident Chambers could fill in further up the field, further shortages at the back may yet see the teenager occupy a more conventional role in defence.
“He’s been excellent in every position,” the Frenchman said of Chambers. “I would consider playing Calum there [in midfield]. But I only have four defenders at the moment.
“From the first to the last minute he has an unbelievable engine. He gets forward and puts crosses in as well.
“It’s remarkable what he’s doing at the age of 19. It’s not often you see that quality at his age. I don’t know what I’ll do yet. Give me a bit of time, but Flamini is the only option I see at the moment.”
Given the problems in defence and midfield, the pressure will be on Arsenal’s attack to deliver, with Alexis Sanchez looking to add to the goal that defeated another Turkish team, Besiktas, in the play-off round
Galatasaray arrive at the Emirates Stadium looking to end a winless run of nine games against English clubs in European competition.
Victory over Sivasspor in the Super Lig on Friday was their first win in four matches in all competitions, a run that included their goalless draw with Anderlecht in the opening game of the group.
Coach Cesare Prandelli has yet to name the same starting XI this season but remains confident whoever he selects will be prepared for the task ahead.
“We are mentally ready and should be aggressive,” said the Italian. “We are representing Galatasaray and Turkey. We have to play our own game and must leave with our heads held high.”
Prandelli will hope talisman Burak Yilmaz can continue the form that sees him lead the club’s scoring charts with three goals in six matches.
The two sides have only met once before in the 1999-2000 Uefa Cup final in Copenhagen, when Galatasaray won 4-1 on penalties after the match had ended goalless.