As was said, barring a severe injury he's a first rounder no matter what. Even if he comes back and other teams double him all year and his stats reflect that, he will go first round of he has a good year this year.
Fact he might want his Sr year to show more of being an every down player, because if you go first round, they expect you to come in ready for what ever they throw at you.
Also with the NCAA allowing it, I don't think the university is going to mind paying insurance policies for first round picks to come back. I would hope not anyway. Because if you don't think Clemson, bama, ECT are covering their first rounders policies, your high.