McCarthy has to deal at the other end of the market to Villa, who have already signed midfielder Jean Makoun from Lyon for £6million.
He has no complaints about having to compete on an uneven playing field but also knows money does not ensure automatic success.
Former Sunderland boss McCarthy said: "Good for Villa. I wonder what Martin (O'Neill) is thinking?
"It seemed to me that they wanted to sell players.
"But good luck to them. There's nothing we can do to affect it."
Source: PA
Source: PA