The midfielder was substituted after receiveing a knock to his ankle in the 1-1 draw at the Emirates Stadium.
"It is not very serious. They say he might be out for the whole of next week because he has an ankle inflammation. But he has not torn anything," said Wenger.
"He is a quick healer usually and a tough boy so I hope he will be quicker than the medical predictions."
The Gunners play Benfica in their final pre-season friendly on August 6, which is followed by an England international friendly against the Netherlands. However, Wenger is unsure whether the 19-year-old will feature in either.
"The England game is on August 10 and I don’t know [whether he will be available]. They told me he might be out next week. If he is out next week, he will not play against Benfica so he will certainly not play for England."
The timing of the fixture against the Dutch, three days before the start of the new season, has been criticised by a number of Premier League managers.