I intended to let this go, but just had to respond.
A high school kid taken in the later rounds will not be put in A ball to start his professional career. Would not happen. If he chooses to to sign, he will begin in short season rookie ball. Nothing wrong with that. The organization wants the young man to learn how to be a professional ball player, and this is the way they do it. Don't take my word for it. Check Baseball America or any other source you choose, none of the high school picks in the 1st round for 2004 or 2005 that signed the summer they were drafted skipped short season ball! One or two may have made it to an A club by the end of the summer, but they didn't start there.
And there are many position players in the minors who were pitchers in high school, and lots of them threw in the 90's.
You may be confusing extended spring training for rookie ball. It isn't the same. Short season starts June 21st and will run through August. Extended spring is for those players not placed on full season clubs coming out of the spring. They work out and play from April until short season starts, then they are placed on a rookie team or higher. So in that sense, extended spring will end soon, June 20th.
Best of luck to Drew, in whatever he decides to do. I hear he is an outstanding player.