Prior to Euro 2020, all teams, including doctors, agreed to a concussion charter stating: "We confirm that if a player of our team is suspected of having suffered a concussion, he will be immediately removed from the pitch, whether in training or match play.".
Global players' union Fifpro said it was in touch with Uefa "to find out why the concussion charter was not applied".
Fifpro has called for football to use temporary concussion substitutes so that players can be replaced while they are being assessed for head injuries.
Trials for concussion substitutes, which do not allow a player to be replaced while they are being assessed but offer additional permanent replacements, have taken place this season in England and other countries.
Headway chief executive Peter McCabe added: "This is another example of football authorities failing to protect the short and long-term health of a player.
"We have continuously been told that football's concussion protocols are fit for purpose and that temporary concussion substitutes are not necessary.
"But here we have yet another example where it is simply not credible to suggest that a concussion could not be 'suspected' or a possible consequence of the impact.".
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