Sitting but not rolling

So my baby is almost 7 months, he will sit completely unassisted and very very rarely falls over. But he’s refusing to roll. He can roll, but he hates to. I play with him on the ground and try to roll him back and forth and he fights me. Should I worry? Any tips or tricks? We’ve done tummy time every single day since the beginning, he rolled for the first time at 3 weeks and continued to do so until he got a little older and then he just stopped. Now like I said when I try to roll him he presses back against me and fights to stay on his tummy