Liverpool youngster Sam Hart has been taken to hospital after suffering a serious head injury during a youth game against Basel.
The 18-year-old was fitted with an oxygen mask and stretchered off the pitch following a collision with an opponent.
Hart was treated by medical staff for 13 minutes before he left the field of play.
The Merseysiders went on to win the match 3-0 to seal their progress in the next round of the UEFA Youth League.
Hart joined Liverpool from rivals Manchester United two seasons ago.