Our flying full-back conceded defeat in his race to get fit before the end of the season a few weeks ago, and McCarthy had his say on the subject after naming his squad for Japan and South Korea.
"The kid really deserves to be playing on the world stage, because he is an absolute star," said McCarthy. "It is a big disappointment for him and me."
Meanwhile, Ciaran Toner, who left Spurs on transfer deadline day to join Bristol Rovers, is heading south again.
The Northern Ireland under-21 midfielder has left Rovers to join third division rivals Leyton Orient.
Milenko Acimovic, who has agreed to join us, has been named in Slovenia's 23-man World Cup squad for the World Cup finals.
Portsmouth striker Mladen Rudonja has also been selected.
Republic of Ireland manager Mick McCarthy has expressed his regret over Stephen Carr not making the World Cup finals.