Why is everyone against manipulating DeLauter’s service time?

Almost every opinion I see about Delauter is that he should start the year with the big league club. To my understanding if you hold the guy back for a couple of weeks you get a whole extra year of control with him.

I understand if he wins Rookie of the Year we get a draft pick- what are the odds of that realistically? I understand he’s been fragile- can he not get hurt anywhere?