England and Arsenal midfielder Jack Wilshere has suffered "a little setback" in his recovery from an ankle injury.
Gunners manager Arsene Wenger revealed the 20-year-old suffered pain in the ankle while running.
"Wilshere had a little setback which is under investigation," said Wenger.
"We don't know yet how bad it is. He has pain again in his ankle (when running).
"We stopped him right away. He is seeing a specialist today, so I do not want to give you any wrong information."
The news will come as a blow to Arsenal, who are five points behind Chelsea and the all-important fourth place in the Barclays Premier League.
It will also be of concern to England boss Fabio Capello as he prepares for his side's Euro 2012 campaign in Poland and Ukraine.
Wilshere suffered a stress fracture in his right ankle last summer while playing for his country and has yet to play this season.
He had originally hoped the injury would heal itself with the help of a protective boot, but he was forced to undergo an operation.