OT, I saw Joe Ross pitch in 2010 in a high school tournament in San Diego when my son's team went out there. He was a stud even then, the best pitcher on Bishop O'Dowd HS from Oakland. (My son actually faced him and grounded out to SS.)
And even more OT, I saw Harper when he was 11 win a HR hitting contents in a tournament at Cooperstown. I later saw him (and knew who he was by then) when he was 15 at a tournament in Atlanta. My son never played against Harper though.