Arizona’s Amazing New Bullpen And Dan Haren

The Arizona Diamondbacks entered 2010 as one of the most intriguing teams in the majors. Showcasing a rotation led by Dan Haren and Edwin Jackson (and with Brandon Webb potentially waiting in the wings) and a fantastically talented young offense including Justin Upton, Chris Young, and Mark Reynolds, there was reason to believe the Diamondbacks could compete with the beasts of the West. Instead, the bullpen failed them, as such names as Juan Gutierrez, Chad Qualls, and Esmerling Vasquez combined to post a 5.47 ERA along with a historically bad -10 WPA (Win Probability Added) and sink any dreams Arizona had of respectability, much less competition.

Diamondbacks ownership, then, when faced with the prospect of paying Haren eight figures yearly to play for a team that was struggling to break 65 wins, decided to ship their ace out. It’s hard to figure out what exactly the thought process was behind this deal. It’s possible that ownership was pressing interim GM Jerry DiPoto; it’s also possibe that there was just a very, very good reason for the “interim” specification. Regardless, the haul for Haren, a pitcher who, although in a bit of a slump, was still coming off of three consecutive sub-3.33 ERA seasons (with similar peripherals), was shockingly low: the perennially mediocre Joe Saunders and a group of rather unremarkable minor leaguers.

Fast forward to May of 2011, and the Diamondbacks are looking remarkably competent. They sit only three-and-a-half games behind the reigning World Champions and the division co-leaders in Colorado. According to Third Order Wins, which adjust for context and schedule, the Diamondbacks have only been a game-and-a-half worse than the division leaders. Nearly all of this improvement can be attributed to a bullpen that is no longer the worst ever but instead has turned itself into an above-average unit in just one year’s time. Thursday night’s victory included three innings with only one unearned run allowed by the Arizona bullpen.

For a variety of reasons, it isn’t nearly as difficult to rebuild a bullpen as it is a starting rotation or a lineup. This concept has certainly manifested itself in Arizona, as the Diamondbacks bullpen now ranks seventh in the majors in ERA and 12th in WPA after ranking dead last in both categories by a wide margin in 2010. The most high-profile move the new Kevin Towers regime employed in this turnaround was the Mark Reynolds trade, which brought back setup man David Hernandez and his 233 ERA+ in return (as well as Kam Mickolio, but his contributions have been, well, not contributions yet). J.J. Putz was also added on a multi-year, multi-million dollar deal, but at 34 and only two years removed from major surgery, the competition for his services may have been limited.

The rest of the bullpen was either on hand or to be had for cheap. Juan Gutierrez posted a 5.08 ERA and a -0.18 WPA for the Diamondbacks in 2010, par for the course for Kirk Gibson’s debut squad. Aaron Heilman and Esmerling Vasquez were therefore bogeys even by these low standards, posting WPAs under -1.00 to go along with 4.50 and 5.20 respective ERAs. Sam Demel was only in Arizona for a limited time after the club acquired him for Conor Jackson, but he was unimpressive in limited action as well.

Here we see the fickle nature of the relief pitcher unleashed. In 2011, Heilman has remained an unmitigated disaster, with a 7.11 ERA, but the worst of the rest of the group has been Gutierrez’s 3.50 ERA, an acceptable mark to be sure. Surely, this remarkable improvement from the bullpen has been a primary factor behind Arizona’s push towards competency.

However, for the three steps the bullpen has taken forward, the rotation has taken a step back. Daniel Hudson and his 2.54 FIP look good, even if the results aren’t there yet, and Ian Kennedy is finally stepping into the shoes vacated by Max Scherzer in the three-way deal headlined by Curtis Granderson’s movement to the Yankees. On the down side, Joe Saunders has been precisely what one would expect Joe Saunders to be in a homer-heavy environment: bad. He sports a 5.02 ERA and a 5.17 FIP, and there’s little reason to expect improvement. Barry Enright has discovered the concept of regression the hard way, as the consequences of pitching to contact with less-than-impressive stuff in Chase Field are making themselves known in the form of a 6.49 ERA. Armando Galarraga was released so this guy could be moved into the rotation. Enough said.

(Full disclosure: Josh Collmenter has actually looked solid this year and may be able to sustain a respectable level of production. He still looks funny, though.).

What if Dan Haren remained, instead of Joe Saunders? Haren immediately rediscovered his form on his move to Anaheim and is once again on pace to post six or more wins above replacement, as he did in both 2008 and 2009 with Arizona. Although there’s no guarantee that Haren would pitch so well in Arizona as well, there were no warning signs of anything other than random variation (not necessarily luck, but also nothing predictive of more poor performance in the future). Perhaps a Diamondbacks team with Haren instead of Saunders is two, maybe three games closer to the division lead. Almost certainly, a Diamondbacks team with Haren in tow is five or six games better (perhaps even seven or eight, with the way Saunders has looked so far) over the course of a full season.

Looking at Baseball Prospectus’s playoff odds, despite the relatively close race in the West, Arizona has a less than one percent chance of playing into October. I don’t think it’s terribly outlandish to suggest that Dan Haren’s presence could add 10, maybe even 20 percent to that total. And I also don’t think it’s an exaggeration to suggest that even the chance at postseason ball this year and the next two years for which Haren are under contract would be worth more than the questionable prospect package now toiling in the Arizona farm system.

The easiest thing in analysis is to suggest that a team made a mistake in selling low. However, in the case of Dan Haren, it is simply too obvious to ignore. The organization had the easiest problem in the game to fix, and had a promising team surrounding the questionable bullpen. If the Haren-led core were still in place with the improved bullpen, the Diamondbacks could be a dark-horse team on the level of the San Diego Padres last season. Instead, the starting pitching will inevitably prove too weak, and the Diamondbacks will watch Joe Saunders pitching in August as the team trails the Rockies or Giants, likely by a double-digit games total instead of Dan Haren in the midst of a playoff race.