Dustin Ackley Slump Data Dump

Perhaps you've noticed that Dustin Ackley is in a bit of a slump. On its own, this wouldn't be of much concern. Everybody goes through slumps. Edgar Martinez hit .246 through the first three weeks of September 1995. They happen, and then they stop happening, and everything is normal.

But Ackley hasn't just been hitting into more outs. He's also been striking out a lot more than he did, and while it's good on one hand to see him join in with the rest of the team in that regard, it's bad because Ackley is our one prayer to turn into a complete hitter. We don't want him to start striking out. We want him to keep making contact and controlling the strike zone.

So I grew curious as to what's been going on. And when I grow curious, I go to the numbers. I split Ackley's season to date into the following four approximate quarters:

We see a low strikeout rate through the first two quarters, and a significantly elevated strikeout rate through the last two quarters. Why? Let's dig deeper. I apologize for this table, but I'm trying to be concise:

We see no meaningful difference in strike rate. We see no meaningful difference in swing rate. The meaningful differences are found elsewhere.

In Q3, we see Ackley's contact rate nose dive, from 88% to 76%. That would certainly explain the hike in strikeouts. More difficult to explain is the sustained strikeout rate in Q4, even though the contact rate mostly recovered. And here, I choose to blame the foul balls. Nearly half of Ackley's swings generated a foul ball, while just over a third generated a ball in play. In any other count but a two-strike count, a foul ball is the same as a whiff, and it could represent a missed opportunity to hit the ball somewhere hard.

Interestingly, look over at that last column. There hasn't been much change in the way that Ackley has been pitched, at least in terms of fastball/non-fastball mix. There was a dip in fastballs in Q2 that sustained in Q3, but Q4 was the same as Q1. There could have been changes in sequencing and/or location, but investigating those would take more work, and nothing jumps out at me right away from the PITCHfx data.

So what's the takeaway? Dustin Ackley has indeed been slumping and striking out a lot, at first because he was completely missing pitches, and then because he was partially missing pitches. I don't know why Ackley has been missing pitches, but I choose to be encouraged by the contact improvement from Q3 to Q4. He won't keep fouling pitches off as often as he has been, and once he turns more of those balls fair, the hits will come, and the numbers will rise.

I'm content to write this off as a rookie adjustment. There could be something more sinister in here that I'm not seeing, but for now, I'll trust Ackley's track record and eye. He's too good for us to worry about based on a few low weeks.