Lucas Torreira was seen leaving Fratton Park in a leg brace and on crutches after picking up an ankle injury in Arsenal's FA Cup win over Portsmouth.
The Uruguayan ace was taken off on a stretcher in the 15th minutes of the Gunners' 2-0 victory after a heavy challenge by defender James Bolton.
Torreira, 24, immediately called out for help as he writhed on the ground in agony.
Medics rushed on to the pitch and tried to treat him as distressed team-mates looked on.
The midfielder was then given oxygen as he was carried off the field, with Dani Ceballos replacing him.
It is understood he was then taken to ambulance for an assessment, where it was decided he would not need hospital treatment.
However, Torreira later spotted wearing a protective boot and was helped up some stairs before hobbling away from the ground on crutches.
Surprisingly, nobody on the Gunners' medical staff thought to help the stricken star carry his backpack.