Chelsea were forced to substitute Oscar during the derby against Arsenal after their creative midfielder suffered 'possible concussion ' in the first half . The Brazilian collided with an onrushing David Ospina in the 16th minute at the Emirates Stadium and was sent to hospital at half time for checks . It looked as if the Arsenal goalkeeper had given away a penalty , but referee Michael Oliver waved away Chelsea 's protestation following the painful clash . Oscar was clattered into by Arsenal goalkeeper David Ospina during Sunday 's London derby . Sky Sports revealed that Jose Mourinho said the Brazilian was taken off due to 'possible concussion ' Oscar was knocked back by the goalkeeper but Michael Oliver did n't award Chelsea a penalty . Didier Drogba replaced Oscar at the break , with Sky Sports revealing that Jose Mourinho had told them the decision was taken because of concussion concerns over the latter . It means Oscar played on for half an hour before being properly assessed , potentially bringing the concussion debate into the public domain again . 'He went to the hospital at halftime , ' Mourinho said . 'We are waiting . We do n't know yet ( if it 's concussion ) . ' Television pundits Jamie Carragher , Graeme Souness and Thierry Henry were all in agreement that it should have been a penalty . Carragher said : 'It was a definitely penalty . It could even be a red card. ’ Henry said : 'The adrenalin will sometimes bring you back to the field . Maybe he thought he could not go back on after sitting in the dressing room for 15 minutes. ’ Oscar appeared in a bad way immediately after being poleaxed by the Gunners ' goalkeeper . He attempted to get up but his arms fell back down to the turf in direct response to the hit . The collision was in the 16th minute but Oscar still manage to play on until half-time .
Chelsea were n't awarded a penalty for David Ospina 's collision with Oscar . Arsenal goalkeeper clattered loudly inside the box . he was sent off at half - time , with mark Drogba replacing him .