Wigan travel to the Etihad Stadium just four days after they beat Millwall 2-0 to reach the first FA Cup final in the club's 81-year history.
However, Platt has insisted that both clubs are focused on their league form.
Platt said: "It is not a case of because we are playing them tonight, we will know how to play them in the Cup final. I don't think it has any correlation whatsoever.
"Roberto Martinez is a good manager and I am sure they are looking at the next four or five games and thinking, 'If we can get away from that relegation threat, then we can enjoy the day'. Retaining Premier League status for them is paramount.
"I am sure if they have it in the bag by then, they will be delighted and they can go and enjoy a Wembley cup final."
Manchester City beat Chelsea 2-1 on Sunday to reach their second FA Cup final in three years.