Former Tottenham midfielder Ryan Mason expressed his incredulity that Manchester United winger Daniel James was permitted to continue playing in Wales' match against Croatia - despite appearing to be knocked out cold.
15 minutes into the Euro 2020 qualifier, with Croatia 1-0 up, James took a blow to the head while competing for a ball with Domagoj Vida, and lay motionless on the pitch.
Medical staff quickly ran on to attend to the player, who managed to get to his feet and make his way off the field.
Just minutes later he returned to the action, but Mason, who suffered a life-threatening injury when he fractured his skull during a match between Hull and Chelsea in 2017, thought James should have been substituted.
He tweeted from his personal account and said: "Daniel James was just knocked out unconscious! Yet 3 minutes later he has been allowed back onto the pitch," followed by a shrugging emoji.
Mason was forced to retire from football due to the risks associated with the extent of his head injury, and since then he has spoken out of the dangers of aerial challenges in the sport, and believes children should be banned from heading footballs.
Twitter users were overwhelmingly in support of his views.
One replied saying: "Football still way behind other sports regarding concussion protocol," while another added: "Football is in the dark ages on head injuries."
Another wrote: "100% Wales will be in trouble."
James has been one of United's brightest attacking threats this season, and has scored three goals in ten games so far for Ole Gunnar Solskjaer's side.
He has also become an important part of the Wales national team, scoring two goals in six caps.
He will next be in action when United take on bitter rivals Liverpool on October 20.
