Painter was rated by some as the top prep pitcher in the draft. Here's all the top rated prep pitchers from 2000 - 2016
2000 - Matt Harrington 2001 - Gavin Floyd 2002 - Chris Gruler 2003 - Ryan Harvey 2004 - Mark Rogers 2005 - Chris Volstad 2006 - Clay Kershaw 2007 - Jarrod Parker 2008 - Ethan Martin 2009 - Matt Hobgood 2010 - Jameson Taillon 2011 - Dylan Bundy 2012 - Max Fried 2013 - Kohl Stewart 2014 - Brady Aiken 2015 - Kolby Allard 2016 - Ian Anderson
As you can see, the success rate isn't that great. One Star, a few solid arms, a lot of mediocrity, and two of the worst draft picks of all time (Harrington and Aiken). HS arms are such a crapshoot. I'm not wishing "bust" on anyone but if a was a GM, I would never mess with a HS pitcher.