Arsenal captain Cesc Fabregas is set to miss next weekend's clash with Manchester United.
Fabregas was substituted at half-time during Saturday's 4-1 win against Portsmouth.
He will have a fitness test today to examine the extent of the injury but could be out for up to three weeks.
'Cesc has a hamstring problem. He will be short for Wednesday certainly,' said Arsenal boss Arsene Wenger.
'If it's a little pull he'll be out for three weeks. If it's just a tightness maybe he can get away for the Celtic game but after 48 hours we'll have a better view.'
He will have a fitness test today to examine the extent of the injury but could be out for up to three weeks.
'Cesc has a hamstring problem. He will be short for Wednesday certainly,' said Arsenal boss Arsene Wenger.
'If it's a little pull he'll be out for three weeks. If it's just a tightness maybe he can get away for the Celtic game but after 48 hours we'll have a better view.'