The Dane has been pleased with the way he has started the 2011/12 season.
"The fact I got the full pre-season has helped me a lot. I feel a lot stronger, a lot better, but I still have more to come, hopefully," Agger told the club's official website.
"I feel I can give some more, have more to offer, so hopefully I can carry on playing games and that will help me.
"Fitness-wise I am happy right now, but as the season carries on you get more games under your belt and you get stronger, quicker and better."