The MLB scholarship program is negotiated and not always 100%. I would think the amount would be determined by how much they want the player. The way the program works is basically the player must start school within two years after he is done with baseball and has five years to use his MLB scholarship money once he starts using the program. One thing to note is once you start using the fund the clock starts ticking on the 5 years. Most that take part time classes during their career pay out of pocket and leave the scholarship for after their playing days are done.
As for holding the spot for admittance, I'm under the impression once you don't show up on campus all bets are off. If you want to enroll it will be based on academic merits alone. (Doubt the coach is going to help you much if you passed on playing college ball)
