We might go over slot on #4, but that of course means going under slot elsewhere. We have the #3 pick; I'm not confident we can save a lot of pool space there. After that, you go under slot by drafting college seniors somwhere in rounds 5-10.
If they do this, that could improve the value of the fourth round pick; the opportunity cost is that there won't likely be much pool room left to go aggressively over slot with a high school pick in rounds 11-13. It becomes an "eggs in one basket" approach, with a pick that's #108 overall.
I have no complaints with the Arrieta and Santana signings - but this is the cost of those signings.