My Organization: Rookie ball: 17 to 20, 21, 22, 23.. Usually those 20s guys are just drafted, typically 22-25 year old guys shouldn't be in Rookie ball SA: 19, 20 - 22 year olds.. Progressing 20s year olds from Rookie ball that aren't ready to jump from Rookie to A ball Or check out Part 2 and Part 5 of this http://traditionsportsonline.com/threads/ootp-player-development.96816/