Gerard Houllier has stressed the importance of every member of Aston Villa's first-team squad and insists they all have a key role to play.
Houllier is keen to ensure his players stay fresh and sharp by making use of all of the talent at his disposal.
He has been impressed by the attitude of his players to improve during his month in charge ahead of Saturday evening's home clash with champions Chelsea.
"We have a squad of 20 to 25 players so not everyone is involved every week," Houllier said. "But in football, we know we need everybody and everyone contributes to the final success.
"Some may not be called up for this game or that game but could appear in two weeks' time and be the hero.
"There are injuries, suspensions, lack of form. Sometimes the tactical approach to a specific game is different so you need different players."