The 32-year-old revamped his career as a relief pitcher with the Seattle Mariners over the past two seasons. Formerly a starter, Perez was very inconsistent, and most of the time not very good. Over the past two seasons, however, Perez finally found his craft, posting a 119 ERA+ in 82 2/3 innings.
In 2013, Perez went 3-3 with a 3.74 ERA and a 1.434 WHIP in 61 appearances, in which he threw 53 innings. He struck out 12.6 hitters per nine innings, and walked 4.4 hitters per nine. He also saved his first two career games. This factored out to a 99 ERA+ for Perez, and a 0.6 WAR. Righties hit a triple-slash line of .256/.323/.463, while left-handers hit .238/.358/.288.
After infamously signing a three-year, $36 million deal with the New York Mets before the 2009 season, Perez only managed to pitch 112 1/3 innings, while posted a 6.81 ERA and a 59 ERA+. He did not even appear in the Major Leagues at all in 2011, while still making $12 million.
Arizona relievers posted a 3.52 ERA last season, which ranked 16th in the Major Leagues. With relievers of the likes of Brad Ziegler, J.J. Putz, newly signed Addison Reed, and now Perez, one can expect the Diamondbacks' relief corps to vastly improve. One can also predict Perez to have another good season, especially now that he moves back to the National League.