In July of 2009, Jack Zduriencik and Dayton Moore swapped Yuniesky Betancourt and some cash for Derrick Saito and Dan Cortes. Betancourt was in the middle of a season in which he would accumulate -1.7 WAR. Amongst Major League players that total was eclipsed only by part-timer Jose Guillen, also of the Royals. Somehow, the Mariners not only got out from under Betancourt's contract without eating the entirety, but also managed to get talent in return.
Almost exclusively a starter with the Royals' farm system, Cortes was intriguing but not overwhelming. He possessed good strikeout rates, but unacceptably high walk rates. From 2008 through 2010, Cortes' performance as a starter was steady at around 20% strikeouts and 14% walks. Possibly doable in the Majors, but not in Double-A.
Then the organization shifted him into the bullpen.
Cortes had just 30.2 innings in the bullpen this season over 126 batters faced, but the difference in results has been striking. Nearly every pitcher benefits from moving to the bullpen from the rotation. The chance to focus on fewer batters means relievers get to exert more effort on the ones they do face. Even still, Cortes took to his new role with a refreshing zest in the midst of a season gone so wrong. With his fastball now holding in the high-90s and reaching triple digits at times, the strikeouts jumped from 20% to 31% while simultaneously the walks decreased from 14% to 10%.
Dan Cortes didn't step onto a big league mound and instantly become 2006 J.J. Putz. We saw some dominance out of him and we saw a complete inability to throw strikes out of him. He demonstrates the ability to one day mature into that sort of shut down reliever, but that day is on hold under the control becomes more repeatable. Still, Cortes only turns 24 next March, is under club control for at least six more years and has all the makings of being a dominating future presence in the bullpen. 2010 can be considered nothing short of a success for Cortes and 2011 looks brighter because of him.