Watford trio Daniel Pudil, Dániel Tőzsér and Essaïd Belkalem have not trained with the club this week ahead of potential international call-ups.
The Hornets have given all three players time off to prepare for anticipated selections for their countries.
Belkalem could be picked for Algeria’s World Cup squad. They play two warm-up matches, against Armenia on May 30 and against Romania on June 3, before jetting out to Brazil.
Pudil will hope to retain his place in the Czech Republic squad for their end of season friendly against Finland on May 21.
The 28-year-old won his first cap in just under two years when he made a substitute appearance against Norway in March.
Tőzsér could be called-up by Hungary for their post-season friendly against Denmark on May 22.
The midfielder was selected in their squad in March but didn’t feature as Hungary were beaten 2-1 by Finland.