Keegan has spent close-on £50million on new players during his time as City boss and this weeks double signing of Michael Tarnat from Bayern Munich and David Seaman from Arsenal have increased the wage bill at the club dramatically.
"Of course the concern about the financial climate and the need to move players out is always there," Wardle told the club's official website.
"Kevin is fully aware of that. But you have to remember that while Kevin has been a great player and manager he is also a very good businessman.
"Kevin knows the financial situation and I am quite sure he will be working during the summer to move players on if he feels that is necessary.
"I feel some players will have to go as it will be to everyone's benefit so the players can get regular football and we can lower the wage bill.
"We have not prioritised as to the number of players who will go but the board of directors have a wage ceiling and then it is down to myself and the manager to make sure we stay to that level."