Jefferson Farfan will miss Peru’s final World Cup group match after suffering a “traumatic brain injury” on Saturday.
The Lokomotiv Moscow forward, 33, was unconscious for “a couple of minutes” after colliding with a team-mate in training and he remains in hospital.
Concussion protocols mean Farfan cannot play against Australia on Tuesday, although Peru cannot reach the last 16.
“It was a scare but he is doing well. The most important thing is he is recovering,” said coach Ricardo Gareca.
“There are some protocols in terms of recovery of a player so that means it is mandatory for a player to remain in hospital for 72 hours until he is stabilised.
“He could be released from hospital but we understand the healthcare of the players is priority.”
The Peruvian Football Federation released a statement saying Farfan “suffered a traumatic brain injury” and that test results have been “favourable for the player”.
Striker Paolo Guerrero added: “He is a great loss for us. We hope to have him back very soon because he is the spark of this team so we hope for a prompt recovery.”