Even looking at stats in the minors is a spotty at best. Two stat lines for last two full years in minors for two "Ace" pitchers. Corey Kluber 2011 - AAA - ERA 5.56, WHIP 1.48, K/9 8.5, K/BB 2.04 2010 - AA/AAA - ERA 3.49, WHIP 1.406, K/9 9.3, K/BB 2.95 Dallas Keuchel 2011 - AA/AAA - ERA 4.12, WHIP 1.265, K/9 5.0, K/BB 2.33 2010 - A+/AA - ERA 3.77, WHIP 1.285, K/9 6.9, K/BB 3.69 Berrios has much better stats in the minors than either of these two, so his chances of becoming an Ace are not out of the realm, nor does it exclude anyone else in the system from becoming an Ace.