Altoona was definitely the home for many of the Pirates' top prospects last year, whether they started the year there, were called up during the season or had their breakout there. The final option is often the rarest, but if there is a level that separates the fringe prospects, it's often Class AA.
Fortunately for the Pirates, they did have some Altoona pitchers break out and jump onto the major-league radar last year. Fortunately for me, I had someone keeping me in the loop of who was about to break out there. In early May of last year, they said to keep an eye on Luis Ortiz.