Davis Schneider spent parts of 4 seasons at rookie and A ball at age 18, 19, 20, and 21
Danny Jansen was at rookie and A for 4 years at age 18, 19, 20, and 21. OPS of 500 and 600
George Springer was in A-, A+, and AA at 21 and 22
Justin Turner was in rookie ball at 21
18 at rookie and A ball is exceptional by itself. Bonilla has hit very well at DSL and rookie. Nimmala hasn't been good, but shown potential. Not sure why you are making up a s*** case to cry about