Rolling in crib

What if your baby can’t roll stomach to back. He’s just started rolling in his crib then I have to go in there and roll him back?

EDIT!! Funny… after 18 minutes of crying and trying to flip, and me stressing if he did flip, he did after 18 minutes and then slept for 8.5 hours on his belly. Didn’t move a muscle the whole 8.5 hours. Longest he’s slept since before 4 month sleep regression. He’s been sleeping 3 hour stretches for months. So weird.