- FanGraphs Baseball - http://www.fangraphs.com/blogs -

Adam Dunn and the DH

Joe Pawl had an excellent piece on Adam Dunn’s continued slump earlier this week, discussing how Dunn’s slump has cost the White Sox a few wins off its record and projection so far this year. His article got me thinking: What exactly is wrong with Dunn this year? Dunn has normally been a model of offensive consistency, hitting at least 38 home runs each of the past seven years — but this year, his power has disappeared, he’s striking out at a higher rate and his balls in play aren’t falling for hits. What gives?

Since it’s so early in the season, it’s easy to say that this is just a slump and Dunn eventually will break out of it. He still only has 200 plate appearances this season — far from the 550 plate appearances needed before power rates stabilize — and as Jesse Wolfersberger talked about a month ago, Dunn had an early season appendectomy that likely threw off his start to the year. The larger sample of success trumps the smaller sample of struggles.

But as the sample gets larger, I can’t help but ask myself: What if that’s not the case? Are there reasons to think this struggle could be more than just a slump?

I think there is, based on two main reasons. But you can decide for yourself.

Reason #1 – Pitch Selection

Going into this year, Dunn always feasted on fastballs. That was the pitch he swung and missed on the least (19%), and pitch type values (2.1 wFB/C) rated him as one of the top 15 best fastball hitters in the majors. Changeups were his kryptonite — he swung and missed on them at a high rate (40+%) and they rated as the pitch he performed the worst against.

This season, though, things are all weird: Pitchers are throwing Dunn more fastballs (68% vs. 54%) and he can’t get around on them (-0.7 wFB/C). American League pitchers are also pitching him differently, using sliders as their main out-pitch, and Dunn’s strikeout rate has spiked to 40%.

Are pitchers throwing him more fastballs because he’s struggling, or is there some reason to believe Dunn can’t hit an American League fastball? I find that hard to believe, but his sudden struggles against the pitch are pretty scary.

Reason #2 – The DH

After speaking out for years against becoming a designated hitter, Adam Dunn caved to the inevitable this offseason and accepted his contract with the White Sox under the assumption that he’d serve mainly as a DH. So not only is Dunn changing leagues and being pitched to differently, but this is his first time he’s working primarily as a DH.

As a Rays fan, I’m especially attuned to the difficulties in asking players to serve in that role. When the Rays signed Pat Burrell before the 2008 season, he’d just come off a 33 homer season and hadn’t posted an ISO below .220 in more than four years. Burrell was turning 32 years old (Dunn is 31), was switching leagues and was asked to DH for the first time in his career. He promptly went out and turned into a giant stinker; his strikeout rate spiked while his power dropped (.146 ISO, HR/FB rate halved), he mysteriously lost his ability to hit a fastball, and his results didn’t improve until he was released from the Rays midway through 2009 season and returned to the National League.

Is it just me, or are there striking similarities between Burrell and Dunn? Obviously, just because one player can’t adjust to the DH doesn’t necessarily mean that another will, but it’s worth remembering that being a DH is difficult. David Ortiz spelled this out for us earlier this year, defending Jorge Posada’s struggles with the immortal words, “…. dude, DHing sucks.” The stats back him up:

“Players also lose effectiveness when being used as a designated hitter; the DH penalty is about half that of the PH penalty. This does vary significantly from player to player – some players hit as well as a DH as they do otherwise, while other perform as badly as they would as pinch hitters.” (The Book, by Tom Tango and Mitchel Lichtman)

Some players can adjust to being a DH, while others struggle with it. And right now, for whatever reason, Adam Dunn is struggling. Will he go the way of Pat Burrell, or will he make his adjustments and improve this season? Only time will tell, but if I were a White Sox fan, I’d start to get a little nervous.