Radamel Falcao went to the ground in first-half stoppage time after a collision with the Nice goalkeeper Yoan Cardinale in Wednesday’s 4-0 Ligue 1 defeat and was taken to hospital for a series of tests.
“Falcao is still in hospital after suffering a concussion on Wednesday,” coach Leonardo Jardim said at a news conference.
“The referees have to pay closer attention and punish actions like this. It should have been a red card in my opinion.
“When a player takes such a risk [to injure an opponent], there has to be some sort of punishment.”
The defeat saw Monaco drop to third place in the Ligue 1 table.