Martin O'Neill is mulling over a replacement for James Milner, and admits fourth spot "seems to be getting further away" for Aston Villa.
The 24-year-old has been strongly linked with a move to Manchester City, with O'Neill revealing that the England international expressed a desire to leave before the World Cup.
City have already seen one bid for the former Leeds and Newcastle player knocked back, and Villa say they will only sell him at the right price.
O'Neill admits that it will be tough to replace Milner, and believes it will be a blow if he does end up leaving the club.
"If we do end up losing a player like Milner, it won't make it easier," he said in the Mail on Sunday.
"You have to replace him, replace his ability and experience, and do it instantly yet do it with someone of probably less value. That is tough."
City have splashed the cash on a number of players so far this summer, and have outspent every other top-flight club by a considerable amount.
O'Neill admits it is becoming harder to compete with the Eastlands oufit, and is pessimistic on his side's chances of breaking into the top four next term.
He added: "Just when you think your team is getting there, getting close to fourth spot, City appear on the horizon with all this money. It seems to be getting further away.
"Well done Spurs for getting into the Champions League - but up until their second last game, they could have finished anywhere from fourth to seventh.
"Top four remains a possibility but to win the title, you need to have the squad. City will have 28 or 29 top-class players available."
