Neil Lennon revealed Celtic have lost 35 players to international duty this week.
The club's Lennoxtown training complex has been like a ghost town as nearly the entire first-team squad and many of the Academy players have departed to represent their countries in matches all over the globe.
The Hoops boss has never witnessed such a mass call-up of players, from youth to first team, for national service.
And although he is happy to encourage his players' international aspirations, he faces a nervous wait until they all return.
"It's right through the club now from Academy level all the way through to the first team," Lennon told the club's official website.
"I think we have 35 involved throughout the club which is quite a remarkable stat really.
"Whilst I would never stop anyone going and representing their country, it can be a very concerning time for me personally, just knowing if the players are going to be okay.
"To compound it all, Scotland are playing Wales (tonight), where I know I have possibly five players playing against one another, and that again is a huge worry for me."
- Neil Lennon