The 19-year-old had be substituted just seven minutes into a pre-season friendly at Emirates Stadium last weekend and is facing a race to be fit for the Gunners trip to Newcastle on August 13.
But taking to Twitter, Wilshere wrote: 'Ankle scan just showed some inflammation. Hopefully will settle down in a few days.'
Injury worry: Jack Wilshere was replaced by Benik Afobe against NY Red Bulls
The information backed up his manager's claim from after the game in which Arsene Wenger said: 'It is not very serious. But it's serious enough that they say he will be out for the whole of next week. It's inflammation but he has not torn anything.
Concerns: Wilshere was one of few positives for Arsenal last season
'He is a quick healer usually and a tough boy, so I hope he will heal more quickly than the medical prediction.
'The England game is on August 10. If he's out next week, then he won't play against Benfica, so he certainly won't play in the England game.'
Wilshere's emergence last season was one of few positives in a desperately disappointing campaign for the Gunners, in which they once again finished empty handed.
Pre-season has hardly convinced Arsenal fans that the current campaign will be any different, with the only additions being Lille's Gervinho and young Charlton full-back Carl Jenkinson.
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