According to the article Mike posted, two teams tried to draft him before, called him and discussed an overslot bonus, but neither reached his number so they didn't draft him. The O's met his number (or offered close enough that he agreed).
Why would he go back? I mean, if this comes back, what if he can’t play baseball next year? He will be worth less.
Take your money now.
So if he didn't get a certain amount he was gonna go to college and try again in a few years. Plenty of guys do that, even when the bonuses being offered are life changing ($500k+).