Each professional sport has its own rules when it comes to how players become eligible for the draft, and whether players drafted will turn pro. In baseball, if you have graduated high school and have not entered college, you are fair game for the draft. If you have gone the community college route, you are fair game for the draft. If you have gone to college, you are fair game for the draft after your junior season or after you turn 21, whichever comes first. The eligibility is automatic- no declarations necessary.
Because of this, being drafted does not automatically mean that you will turn pro. To use an example near and dear to UCLA baseball fans, Gerrit Cole was drafted in the 1st round (28th pick overall) by the Yankees out of high school. He turned down the Yankees, came to UCLA, and was the top pick overall in the draft three years later after his junior year as a Bruin.
But Gerrit Cole and Adam Plutko (6th round pick out of high school who came to UCLA) are exceptions to the normal trend in recent years. Normally, if a recruit is drafted in an early round, that recruit turns pro. In 2013, this trend even extended to the 11th round (last day of the draft), when both recruits selected in that round opted to turn pro.
The 2014 draft started yesterday. And the 1st pick overall, as expected, was Brady Aiken, a pitcher from Cathedral Catholic HS in San Diego. There is also a recruit listed in the 2015 UCLA list of commits- Brady Aiken. They unfortunately happen to be the same person. So there goes an instant insert into next year's pitching mix.
Baseball America has a database with the projected 2015 draft through number 500. The staff making these projections are talking to the same scouts and other sources who are circling around the top prospects. So, if an actual selection is wildly different from the projection, the prospect is likely to know about the divergence. If a prospect is drafted earlier than expected, that could tilt the odds in favor of turning pro. If a prospect is drafted later than expected, that could tilt the odds in favor of going to college and moving up to their "right" choice after the junior season.
The second Bruin recruit selected yesterday was Grant Hockin, a pitcher from Damien HS in LaVerne. He was the 61st overall pick (taken in the 2nd round). He had been projected by Baseball America to be a 3rd round choice, at #109. Since he moved up in the draft, it is hard to imagine him coming to Westwood. So that is a second pitcher lost from the pipeline.
Rounds 3-10 will take place today. More updates as this unfolds.