Alex Iwobi left the field on a stretcher during the second half of Everton's FA Cup third-round tie with Manchester United.
The Nigeria international was replaced by Abdoulaye Doucoure after just 51 minutes of the tie as he was involved in a heavy tackle with United full-back Tyrell Malacia.
Captain Seamus Coleman was one of the first Everton players to respond as he quickly signalled for further help from the Toffees' medical department while comforting the midfielder who lay in agony on the turf.