Carson, who spent last term at Charlton, will spend another season away from Anfield after pleading with Benitez for the chance of regular football.
Benitez has refused to sell Carson this summer, and had told the player he will be Jose Reina's number two.
But with Carson now a regular in the England squad and the Euro 2008 finals at the end of the new campaign, months of activity would not have helped his cause.
Benitez said: "I have talked to Scott and he understandably wants to play every week.
"He wants to maintain his position in the England squad. And it would suit us if he was playing and improving, and that is what will happen."