The Potters have been busy in the transfer market this summer bringing in four new signings to bolster Mark Hughes' squad.
A number of players have been linked with moves out of the Britannia Stadium, including experienced striker Peter Crouch, and Coates admits players will leave as they look to maintain the size of the squad.
"There is certainly no financial pressure to sell," Coates told the Stoke Sentinel. "It's a question of the numbers and the balance of the squad.
"There comes a point when a squad can become difficult to manage because of the numbers, so size is very important.
"But ultimately, of course, it is always down to the manager who comes and who goes."