Agger has yet to reach his peak physical fitness and is carrying a minor knock, and has also been linked with a summer move out of Anfield.
However, Rodgers insists that the Denmark international centre-back remains a vital part of his team for the new campaign.
"We have a behind closed doors game for him this weekend to help his match fitness," he is quoted as saying by Talksport.
"Daniel is fit, but we have to make sure his physical condition is up to speed. He wasn't going to play and as that was the case, I wanted him to use that time to work on his physical condition."
Liverpool will start their Premier League campaign with an away game against West Bromwich Albion on Saturday, August 18.