Let's look at the amateur drafts from 2008 to 2011 and see who is still in the system (either in the Majors, or currently assigned to a full-season minor-league team):
2008
Jason Castro (1st Round): Houston
Jordan Lyles (1st Round, supplemental): Oklahoma City
Ross Seaton (3rd Round): Corpus
Luis Cruz (9th Round): Lancaster
Rene Garcia (35th Round): Corpus
2009
Jio Mier (1st Round): Corpus
Jonathan Meyer (3rd Round): Corpus
Enrique Hernandez (6th Round): Corpus
Dallas Keuchel (7th Round): Oklahoma City
Ben Orloff (9th Round): Corpus
Erik Castro (10th Round): Corpus
Jake Goebbert (13th Round): Oklahoma City
J.D. Martinez (20th Round): Houston
2010
Mike Foltynewicz (1st Round): Lancaster
Delino DeShields (1st Round): Lancaster
Vincent Velasquez (2nd Round): Quad Cities
Austin Wates (3rd Round): Corpus
Bobby Doran (4th Round): Corpus
Roberto Pena (7th Round): Quad Cities
Jake Buchanan (8th Round): Corpus
Tommy Shirley (9th Round): Lancaster
Andrew Robinson (12th Round): Corpus
Jordan Scott (14th Round): Quad Cities
Chris Wallace (16th Round): Oklahoma City
Alex Sogard (26th Round): Corpus
2011
George Springer (1st Round): Corpus
Nick Tropeano (5th Round): Corpus
Brandon Meredith (6th Round): Lancaster
Jonas Dufek (9th Round): Lancaster
Kyle Hallock (10th Round): Quad Cities
Zach Johnson (15th Round): Lancaster
Tyson Perez (17th Round): Lancaster
Mitchell Lambson (19th Round): Lancaster
Matt Duffy (20th Round): Lancaster
Drew Muren (22nd Round): Lancaster
Jesse Wierzbicki (24th Round): Quad Cities
Chase Davidson (41st Round): Quad Cities
Chris Epps (45th Round): Lancaster