Argentina is currently on the UK's 'red travel list,' meaning the four Premier League players will be forced to isolate for 10 days on their return from South America.
As per this article. Giovani Lo Celso and Cristian Romero will miss Tottenham's Matchweek 4 and 5 fixtures if they go on international duty as they are required to quarantine for 10 days.
For me this is a BIG issue. And depending on the rules other players may have to quarantine for a long time as well.
Its important to say though that Liverpool have blocked Firmino/Alisson/Fabinho and Salah going on international duty (reportedly) SO I don't see why we couldn't do this either.