Arsenal boss Arsene Wenger has confirmed that Jack Wilshere faces a battle to be fit for Saturday's North London derby against Tottenham.
The 18-year-old was expected to make his first start for England in Wednesday's friendly against France but was ruled out of the 2-1 defeat due to a back problem.
The midfielder is now back with the Gunners, for whom he has already made 14 starts this season, and will be assessed ahead of the Emirates clash.
"Jack has a test," Wenger told the club's official website. "He has a little strain of a little muscle in the back and is not in full training at the moment.
"We will know more on Friday about whether he is available for Saturday."
Arsenal had several players involved in the friendly at Wembley, including Theo Walcott, Kieran Gibbs, Bacary Sagna and Samir Nasri, while Gael Clichy was an unused substitute for France.
Van Persie boost
Most of Wenger's players were away on international duty this week, with striker Robin van Persie providing the Gunners with a boost by coming on for the second half of Holland's 1-0 win over Turkey to step up his recovery from an ankle injury.
However, Andrey Arshavin and Tomas Rosicky have picked up problems and will also be monitored ahead of Saturday's derby.
"We have to assess Arshavin, who has still to come back [from Russia]," said Wenger.
"Rosicky is coming in later too. He had a tight hamstring, but should be okay.
"Van Persie had 45 minutes, which was agreed. He needed that. We had someone at the game and he looked quite sharp."
Manuel Almunia (elbow), Thomas Vermaelen (Achilles) and Abou Diaby (ankle) remain out, although Almunia could be back in contention for next week's Champions League trip to Braga.
"He is back in full training," Wenger added.
"Almunia needs a few more days because he has been out for a long time, but he should be available for next week."