Scouts from clubs across the globe will be flocking to Brazil this summer in the hope of spotting a potential star of the future.
Most will be looking away from the established footballing nations, with the depth of their talent well-documented.
They will, however, have to tread carefully as history dictates that shopping in a World Cup window is not always the best idea.
McCarthy, who has worked in international management and in the Premier League, says 'monumental muck-ups' have been made in the past as a result of poor judgements being made on players who are not right for the English game.
He told Ipswich's official website: "All the Premier League managers and scouts will be going out to Brazil or watching games on TV.
"They won't be looking to pick up the top players from countries like Italy, Germany and France, they will be looking at other countries that are under the radar and they might see a player they like.
"The World Cup will have a bearing on how Premier League managers look at their squads for next season and it will also have a knock-on effect on who they might let go - either permanently or on loan.
"Some managers down the years have made monumental muck-ups in signing players after World Cups though.
"You see players playing for their country and sometimes they play way above what they normally do. Obviously they would have done well to get to that level and then they go and have a great World Cup.
"Then they come to England and you wonder what happens. That has happened to a lot of players. I don't think the World Cup is the best place to judge them."