Both men were set to represent their nations over the next few days, but have picked up knocks since Saturday’s 2-2 draw with Wigan Athletic, and subsequently withdrawn from travelling.
Ramírez was set to be part of Uruguay’s match against Spain in Qatar on Wednesday, whilst Clyne had been called into the England Under-21 squad set to face Sweden.
Clyne’s Saints teammate Luke Shaw does, however, remain in line to appear for Stuart Pearce’s side at Walsall’s Banks’s stadium on Tuesday.
Artur Boruc, Steven Davis, Vegard Forren, Calum Chambers, James Ward-Prowse and Lloyd Isgrove will also all join up with their national squads this week.