Houllier is hoping regular action in the Championship will help the duo become better footballers and prepare them for another assault on Villa's first team next season.
"Nathan went out because we recently got Darren Bent," said the manager..
"We thought it would be good if he could get some games under his belt.
"It was excellent to see him score last week.
"Bannan is the same. I want to keep him as well but Fabian Delph seems to be back from his injury and we've got Stiliyan Petrov and quite a lot of other players in that position.''