As
@737Max said, we can't do a long-term deal with him due to his age (and we also can't lavish a huge salary on him just yet either, although there'll be big bonuses).
As soon as he's old enough, he'll be signing a newer deal, 5-6 years and a better base salary.
There's a good chance that there'll already be a better deal attached to the current one which can be activated by the player when he's 18. It was normal practice when we brought kids in on scholarship deals (under which they get paid peanuts) that there would be a pro deal attached to it which would be on better terms, and would be signed as soon as they were old enough.
Nothing to worry about here.