One day after Keith Law posted his farm system rankings, Baseball America puts their list out and they have the Pittsburgh Pirates slightly lower than Law. They rate the Pirates as the 11th best farm system(subscription required), three spots below yesterday's ranking.
While BA does have them ranked lower, they still say that the Pirates have a strong farm system. They like the Pirates depth at shortstop and John Manuel named Jordan Luplow as a breakout candidate. Luplow had a .957 OPS in the second half last year, so you could say that he already started to breakout.