Arsenal striker Robin van Persie has sustained a 'partial fracture' to his foot.
The Dutch player suffered the injury when scoring the equalising goal in today's 2-1 Barclays Premiership defeat of Manchester United.
After watching captain Thierry Henry score a stoppage-time winner, Gunners boss Arsene Wenger revealed he had hoped to let substitute van Persie - currently the club's top scorer - rest until United's opener forced his hand.
The 23-year-old had been struggling with an ankle injury in the build-up to the game.