Slow Your "Roll" Nathan

Last night Nathan rolled over in his crib after I laid him down for the night. I turned him over and thought it was a 1 time thing. Then this mornig after I fed him & got him ready for the day, I laid him on his activity mat. Then next thing we notice is he rolled over from back to belly. So I laid him back on his back and what do you know....he did it again. I can not beleive he is rolling already! He need to slow down.....