Former #1 overall pick Mark Appel (Monte Vista HS, Danville & Stanford University) will make his MLB debut for the Phillies on June 25th. Here is the article from the Phillies website detailing how he got here (incidentally, replacing another former BAWSr, Connor Brogdon, due to injury). Mark was at the event in 2008.
Here is the link to the article on ESPN.com
Regarding Garrett Hill and his MLB debut, here is an article in the Petaluma Argus Courier.