The 22-year-old has undergone a hernia operation after sustaining a stomach injury in training a month ago.
“He has a hernia and had surgery on Thursday. He looks like he will be out for between four and five weeks,” Arsenal boss Arsene Wenger told the club’s official website.
“At first he had an abdominal strain, certainly caused by the fact that he had a hernia already. When the strain was healed we discovered that he had a hernia. We had a fear that could be behind it so we decided to do the surgery.”
