Newcastle United's medical team have been in contact with Switzerland after Fabian Schar was knocked out playing for his country.
Schar played on after an "awful" clash of heads during Saturday's Euro 2020 qualifier against Georgia.
The Newcastle defender collided with Georgia's Jemal Tabidze, and opponent Jano Ananidze stopped the prone Schar swallowing his tongue.
Schar, however, was deemed able to continue after treatment, and Switzerland went on to win 2-0 in Tiblisi.
In the Premier League, a player must be taken off if there is a confirmed or suspected loss of consciousness.
There are also Football Association and Premier League guidelines which set out how quickly a player can return for a club. If a player is believed to have suffered a concussion, he must not play a competitive game for at least six days.
Switzerland play Denmark at home tomorrow night in a Euro 2020 qualifier.
Schar, suspended for Newcastle's April 1 game against Arsenal at the Emirates Stadium after picking up 10 bookings, was shown footage of the incident after the game.
"It looks awful," Schar told told Blick. "I can't remember anything.
"I was out for a few seconds. My skull is still humming, and I've got neck ache and a bruise on my forehead, but it was worth it."
Newcastle have made no comment on the incident, but the club's medical team are understood have been in contact with their counterparts in Switzerland since Schar clashed heads.