One might assume so, or it could be a late bloomer, or a health issue.
I guess I'd want to compare weights to siblings, ask about interactions,
any temperament tests, early neural stimulation and get a health check.
Are you looking for lower energy, or lower drives?
Thanks for the feedback, I am looking for a dog who will have a lower need for exercise. I will be jogging with my gsd for an hour daily, but I live in an apartment so I will not be able to give him too much more exercise than that. I have owned a german shepherd as a child and cannot see myself having anything else. However I do not want to put a dog in a bad situation where he does not get enough stimulation or exercise. The breeder of this particular puppy tells me that he is usually content taking a nap or just lounging whenever she takes the puppies out into the yard to play and exercise.
I think a lot goes in how you raise them too. Diabla is a lot like Lucina's pup, high drives but moderate energy (people often get those mixed and thinks that a high drive dog will be bouncing on the walls) She goes with me in the car wherever I go, wich means her day is divided into be one or two hours on her crate and 15-20 minutes training or fetching her ball. She's already so used to that routine that it doesn't bother her at all to jump on the car even when she knows that the game is over.
I am not sure if you know this or not, since it seems like a while since you have had a GSD, but you have to be careful with excercise like jogging on hard surfaces until the growth plates are closed. Right now an hour is good for you but it would be bad for a pup or young dog. Talk to the breeder about when you can start the jogging with your pup.
As the others have posted there is a difference between drives and energy levels.
Excercising the brain can be just as tiring on a pup/young dog as lots of excercise. I know that some tracking training with my young dogs and they were tired. Processing all the scents and figuring out what they are suppose to be following in very tiring.