Long article on the CBA by Jeff Passan. One interesting nugget, far down in the article:
• High-school players can formally opt out of the amateur draft instead of just telling teams not to draft them.
Prior to this, there was no real mechanism for high school kids to either "enter" or "not enter" the draft - there has been no need for kids to "declare" for the draft. If they came to the attention of a major-league club, they could be drafted - even if they didn't know they were being considered.
Evidently, there is still no formal requirement for kids to "declare" for the draft - but there will be a formal process for them to exclude themselves, if they have no intention of signing a professional baseball contract (e.g., if they're dead-set on going to college).
What's not clear is what the real effect of a kid opting out will be over the longer term - he's presumably not eligible to be signed as a non-drafted free agent (if they didn't address this, certain agents will have a field day!), for at least some period of time. What happens if he doesn't matriculate at a college? Is he treated the same as a drafted player who fails to sign?