"Costing a lot of money doesn't guarantee anything. You have to earn the right to play. David knows the situation here.
"It is great that we have terrific competition for places. I made 10 changes from the win at Blackburn last Sunday to the win at Burnley on Tuesday and they are all good players, all doing a good job.
"I roughly know my best team now but that can change. You only need a bad defeat or a player dropping his form and it is also sometimes dictated by a particular opposition.
"Otherwise you would pick the same team week in, week out if they all stayed fit."