Arsenal midfielder Granit Xhaka responded to Roma boss Jose Mourinho commenting on his Instagram post.
Xhaka, who recently tested positive for COVID-19, made an unrelated post on Instagram in recent days.
Mourinho posted a comment, saying: "Get the jab Granit and be safe."
The Portuguese boss was referencing the COVID-19 vaccine, with Xhaka said to be unvaccinated at present.
Xhaka responded: "Thank you mister."
Swiss football chief Adrian Arnold said, per the Mirror: "Granit Xhaka was not vaccinated. He's a player who isn't vaccinated. We left this up to each player, it's a personal decision of each player – just like any other person in Switzerland.
"We have issued a recommendation that everyone vaccinate. But he decided for himself personally. And it is also his right not to be vaccinated."