Dawson has featured in all but one of Tottenham's matches in the competition this season but is set to be watching from the bench as Redknapp pairs Jonathan Woodgate with club captain King, whose appearances continue to be limited due to persistent knee trouble.
Redknapp was quick to praise Dawson for his contribution to the side but maintains he will always include King when fitness allows.
'Dawson has been fantastic for me and done a great job,' said Redknapp.
'But when Ledley plays we seem to win. He played at Manchester City when we won, he played at West Ham when we won and at Hull when we won.
'You just wish you could get Ledley on the pitch more because when he plays he has a presence about him.
'Ledley's a very important player to us, so we'll have to see how he is for Sunday.'
Before Sunday's final Tottenham have another cup game on Thursday, with Redknapp voicing his displeasure at the build up of fixtures faced by his side.
Redknapp looks set to send out a youthful side for the Uefa Cup second leg against Shakhtar Donetsk to give the bulk of the first team time to recover for the Carling Cup decider, with Woodgate already a doubt after picking up a nasty head wound against Hull.