McCarthy has not played at all for Everton this season, after suffering with injury.
The Republic of Ireland international was controversially selected for his nation over the past two weeks, but he did not play in either of Martin O’Neill’s side’s matches.
And Koeman is glad that McCarthy has returned to Everton in good shape, with his comeback now edging closer.
"He will do more training sessions, get game time in the under-23’s on Tuesday and then I think he’s ready for the first-team," the Dutch boss said.
Koeman and O’Neill have a strained relationship, as the Ireland boss has often used McCarthy when the midfielder has not been fully fit.
The Irish managed to do without McCarthy last week though, and they still beat Wales to move a step closer to booking their place at next year’s World Cup.
Everton’s next match comes against Burnley, which McCarthy will miss, but the combative midfielder could be included in two weekends’ time, when the Toffees take on Arsenal.