Two indicators to explain Corey Dickerson’s August decline

Going into the season, many wondered out loud if the Pittsburgh Pirates’ newest outfielder would carry his reputation with him to PNC Park.

Fair or not, that reputation — that Corey Dickerson slumps hard in the second half — seemed to not bother the Pittsburgh Pirates much. Of course, not much could bother a club about a player when said player is acquired for the low, low price of Daniel Hudson.

That reputation stems mainly from Dickerson’s 2017 post-All Star Break foibles, which saw precipitous drops in slugging (.408, down from .548), OBP (.282!) and wRC+ (80, as opposed to a stout 139 first half figure). This along with a spike in strikeout rate of 28.2 percent in the second half created enough of a cloud of doubt around him that the Rays decided to cut bait earlier than many thought they might.

Regardless, his second half troubles are the Pittsburgh Pirates’ problem now. Of course, we’re talking mainly about the month of August here, a month in which Dickerson could quite possibly end up homer-less. Here are two catalysts that could explain why.

Hamstring to blame?

Let’s start with the least-quantifiable factor. On July 24th, he exited a game with a hamstring injury after running a ball out to first. He would later make a trip to the DL.

Hamstring injuries have been known to sap power for a time after a player returns, and that could explain some of the following:

(Note: for pre-August figures, a minimum of 100 batted balls was set. For August, a minimum of 25 was set)

Dickerson’s average exit velocity has actually not dropped all that much, but he is doing far less in August with a similar figure. Is the hamstring injury still affecting his ability to drive the ball? Has it turned some doubles into singles? Possibly.

Won’t get fooled again

The Pittsburgh Pirates knew they were getting something of a free swinger in Dickerson, who posted a strikeout rate of 23.9 percent or better in each of his last three seasons. Dickerson’s patience shown early in the season turned heads, if only chiefly due to how out of character it was.

In August, however, Dickerson’s bad habits have started to rear their ugly heads again:

Breaking balls are once again the bane of Dickerson’s existence, with an ugly 46.2 whiff rate overall. Though he has had elevated strikeout rates against breaking pitches previously this season, he has never been getting outright fooled like he currently seems to be.

Dickerson has only seven called strikes against breaking pitches in August, so he is truly getting lured into swinging away. Overall, regardless of pitch type, Dickerson is also getting into less favorable counts slightly more often:

Here I have highlighted the biggest increases in counts by percentage. 0-2 and 1-2 saw the biggest jumps. Dickerson seemed to be able to avoid getting into these unfavorable counts much more regularly prior to August.

Dickerson is still batting for a high average (.297 as of this writing), but without the production he carried earlier in the season, it rings very hollow.

There are still those out there who clamor for Dickerson to receive an extension to stay with the Pittsburgh Pirates past his last arbitration year in 2019.

Perhaps now those same folks can be persuaded to see a bit more from the 29 year-old veteran before committing to him further.