D., My son did the exact same thing and he really never did roll. All of his motor skills were on the upper age range for normal. He only crawled one day and then walked (at 15 months). He didn't pull up until 12 months but the doctor kept saying it was okay. I have a child development background so I was worried. However he did tell me not to use any baby equipment most of which inhibits motor skills for kids. As I look back I think it was related to his personalizty and risk taking. He never did wild stuff like alot of boys.
He was a real talker though and talked early and a lot. I always feel like kids are either more movers or talkers. I am not sure if research shows that.
Give him lots of "tummy time" which strengthens his trunk and neck muscles. Go on the Children's Memorial web site under Occupational Therapy and I think they have some good info.
I didn't give my son enough tummy time I know that. He hated it and so I didn't do that. A.