Cause and Effect: Behind the Bullpen’s Struggles


At this point, no one needs to be told that the Arizona bullpen has been struggling mightily. Aside from the surprising performances of Matt Reynolds and Tony Sipp, things have been a let down. Since the re-made bullpen was supposed to be an area of strength for the club, the results to date are quite disappointing. When the division race gets tight down the stretch, our minds may wander back to the bullpen’s early-season issues.

The bulk of the struggles have largely been limited to those in high-leverage situations, notably JJ Putz and David Hernandez. I was curious to know if these guys were failing to perform like they have in the past or whether this was just a blip on the radar that could be attributed to bad luck and small sample sizes. I wanted to know if this was something that we should be concerned about or whether we could reasonably expect this difficult stretch to pass. After all, they wouldn’t be the first major league pitchers to get off to a slow start, right?

Digging through their performances, pitch-by-pitch, a few things jumped out at me. We’ll take a look at both Putz and Hernandez individually to see just how they’ve been getting exposed.

Arizona Diamondbacks relief pitcher J.J. Putz. IMAGE: Ed Szczepanski – USA Today Sports

It’s no secret that JJ has been excellent for the Dbacks over the last two seasons. He’s built that success largely by doing three things: striking out a lot of batters, issuing very few walks and limiting the number of homeruns he’s allowed. In 2013, he’s still recording a lot of strikeouts (12.8 K/9) but the walks are killing him. He hasn’t posted a walk rate like his current one (4.97 BB/9) since 2009 with the Mets. He’s walked less than two batters per nine innings in each of the last two years, so this current spike is unexpected. Making matters worse, JJ has already surrendered three homeruns through 12.2 innings in 2013 after allowing only four all of last year (54.1 IP) and only four in 2011 (58 IP). If there’s anything we know about pitching, it’s that walks and homeruns are a good recipe for disaster. So far, JJ is way above his norms in both categories.

What’s leading to these issues? Looking at Pitch F/X data, it’s clear that his velocity is down throughout his arsenal. We don’t know if this is simply a matter of him building up early season arm strength or if he simply is losing velocity. At 36-years old, a drop in velocity wouldn’t be surprising. He’s also altered his offerings to hitters, throwing his fastball less often and using his slider more. The slider has been simply average so far and his fastball hasn’t been nearly as effective as usual. But Putz is most notable for his splitter. When he commands the hammer, it’s lights out for hitters. Unfortunately, the splitter is notorious for being one of the most difficult pitches to command in baseball. So far, JJ is having trouble with the pitch and it’s getting crushed. Because of his struggles with throwing consistent strikes, hitters are taking more and chasing less, forcing him to come over the plate and risk getting hit hard. And that’s just what’s happened.

David Hernandez’ struggles have also seemingly come out of nowhere. His recipe for success in the past has been high strikeout rates and not giving up the long ball. Never a control artist, Hernandez is currently right on par with his career walk rate (3.95 BB/9), but his strikeouts are down from last year. More importantly, he’s been burned by the homerun, as opponents have already put four offerings over the fence this year (13.2 IP). He allowed only four dingers in each of the last two years, so his current homerun rate is surprising. Given his propensity to walk hitters, the homeruns are painful. For example, on May 1st, he entered the 8th inning protecting a one-run lead. Hernandez walked two hitters before giving up his latest long ball, a three-run heart-breaker that gave the rival Giants a lead they wouldn’t surrender.

Arizona Diamondbacks relief pitcher David Hernandez. IMAGE: Ed Szczepanski – USA Today Sports

So where has David strayed? Why is this happening now? Like Putz, Hernandez has altered his repertoire. He’s throwing his two-seamer 30% more often than last season. This has largely come at the expense of his four-seam fastball, which he’s using 40% less than in 2012. What’s behind this shift is unclear, but it’s not working as his two-seamer is getting hit hard and has been costing him dearly. David’s curveball, his best offering last year, has also been far less effective in 2013. On the bright side, his changeup has improved but without fastball success, the changeup’s usefulness is limited. Like JJ, batters are taking more and chasing less since Hernandez is struggling and hitters know it. They are taking advantage of the situation by forcing David to throw strikes and jumping on hittable pitches.

I wanted to be able to blame the poor results of the back-end of the bullpen on bad luck. Unfortunately, the BABIP of both JJ and David are right in line with their career averages, showing that we can’t just hope for regression to the mean. Instead, there is some puzzling information within just how they are pitching. Will JJ’s velocity pick back up? Can he command the splitter and get it back on track as one of the game’s premier put-away pitches? Will David either get his two-seam fastball under control or start using it less? What about his curve? Can both of these guys find a way to keep the ball in the yard?

The Dbacks season rests in their hands and given the competitive nature of the division, there are sure to be a ton of close games as the season wears on.  Can they rise to the occasion and iron out their issues? We certainly hope so.