The 18-year-old centre back had been tipped to make his first-team breakthrough for the Premiership club during the second half of the campaign, having missed the first half with back trouble and then a foot problem. His latest setback came in an Under-19 match for Arsenal and an operation this week has left him on the sidelines again.
"Philippe had surgery on Tuesday because he broke down again," Arsenal manager Arsène Wenger told the club's website. "We wanted to push it as far as we could but this time we had to take action. The surgery has gone well but you can say that his season is 90 per cent over."
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