Yesterday, the Mets officially acquired pitchers Adrian Rosario and Danny Herrera from the Brewers to complete the mid-season trade featuring then-closer Francisco Rodriguez. The knee-jerk reaction by most Mets fans have been, “Who the heck are these guys?” While neither player appears to be a future superstar, it is possible both pitchers could be pieces in the Mets bullpen.
Rosario has both starting and relieving experience, but it’s obvious his destiny is as a bullpen arm. In his first three seasons in the Minor Leagues (2007 to 2009), he owned a dismal 4.94 ERA, 1.60 WHIP, and 1.62 as a starting pitcher. However, in 2010, the Brewers decided to move Rosario to the bullpen. Between Rookie-Ball and Single-A, the righty posted a fab 3.50 ERA, 1.23 WHIP, and 3.28 K/BB (including a 11.5 K/9). Rosario continued his relieving success this season, hurling a 1.34 ERA, 0.98 WHIP, and 3.50 K/BB (with a 11.2 K/9) in 33.6 innings for Single-A.
Despite his success out of the ‘pen, upon promoting Rosario to Advanced-A, the Brewers put him back in the rotation. The 21 year-old has struggled mightily again as a starter, hurling a 5.83 ERA, 1.68 WHIP, and 1.18 K/BB in 66.3 innings. Based on Rosario’s extreme role splits, it would be surprising if Alderson didn’t put Rosario back into the bullpen. Assuming the righty is bullpen bound, Adrian Rosario could potentially be a solid reliever for the Mets in 2013 or 2014.
While Rosario’s potential contribution is more down the line, Danny Herrera’s could be as soon as next season. The 26 year-old lefty already has a decent sample size of Major League experience, having tossed 93.6 innings from 2008 to present. Originally a Texas Rangers farm hand, Herrera was dealt along with Edinson Volquez in the Josh Hamilton deal. The tiny left-hander (only 5’6″) dominated the Minor Leagues despite his small stature, owning career 2.76 ERA, 1.06 WHIP, and 3.99 K/BB.
Herrera’s first full-season in the Major Leagues was in 2009 for the Cincinnati Reds, where he posted a solid 3.06 ERA, 1.41 WHIP, and 1.83 K/BB in 61.6 innings. He also sported a good 50% GB% and sustainable .310 BABIP. However, Herrera wasn’t able to maintain his success in 2010, and he saw his innings drop from 61.6 to just 23. The lefty spent most of 2010 in Triple-A, where he was flat-out dominant (4.30 ERA, 0.95 WHIP, and 6.8 K/BB). Despite the success, Herrera was placed on waivers, and claimed by the Brewers in 2011. The now 26 year-old has only seen 1.6 Major League innings this season, but his future as a big league reliever is far from over.
Even though on the whole, opposing hitters own a favorable .302/.362/.442 line against him, Herrera has limited left-handed hitters to just a .213/.278/.306 line. It is possible that the left-handed Herrera could have a bright future in a limited, special role for the Mets. Herrera might not be the answer to the Mets sole lefty in the ‘pen, but he would be a warm addition as a much-needed second lefty.
For those still unimpressed with Rosario and Herrera as the bounty for Francisco Rodriguez, one has to recall the giant obstacle that was Rodriguez’s $16.5 million 2012 option. Even though K-Rod later waived his 2012 option, that scenario was simply not feasible prior to the trade. Given Alderson’s disposition, netting two bullpen arms, while subtracting Rodriguez’s bulky and hindering contract, was undoubtedly a prudent decision.