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How Matt Carpenter Became the National League’s Hottest Hitter

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The slugger has exorcised his shifty demons to help orchestrate the greatest offensive turnaround of 2018.

Benny Sieu-USA TODAY Sports

(Author’s note: any statistics included in this article were collected prior to the Cardinals’ game on Wednesday, June 27th.)

However turbulent and unpredictable life may seem, we live in a world that still offers a few evergreen constants: death, taxes, and the notion that slander against one Matthew Martin Lee Carpenter will not be tolerated here at Viva El Birdos dot com.

The first six or so weeks of the season were a dark time for us newfangled wRC+ nerds entrenched in the #TeamMarp camp. Among the 243 batters who logged at least 100 plate appearances through May 15th, Carpenter’s wRC+ mark of 60–or 40% below the league average hitter–ranked 224th, especially alarming for a player who produces relatively little in terms of defense and baserunning. But since then? We have been rewarded for our faith in Matt Carpenter with the second greatest hitting spree of his entire career.


Carpenter is tied for the distinction of being the 11th most valuable position player since 2013, and his current hot streak features the second highest apex in that timeframe. His 7.2 fWAR–tied for fourth in MLB and second in the NL–campaign in 2013 “only” peaked at a sterling 40-game rolling wRC+ of 188, which still falls short of what we are currently witnessing. In fact, Carpenter’s 199 wRC+ from May 16th onward is tops across the entire National League. (Apparently this “Mike T.” fellow in the AL edges him out.) Carpenter has enjoyed the greatest 180° turnaround in all of baseball, and it isn’t particularly close.

Largest Changes in wRC+ (Minimum 100 PAs in Both Timeframes)

Name Team ≤May 15 ≥May 16 Change
Name Team ≤May 15 ≥May 16 Change
Matt Carpenter STL 60 199 139
Derek Dietrich MIA 76 194 118
Kendrys Morales TOR 36 145 109
Tommy Pham STL 162 54 -108
Ian Desmond COL 33 138 105
Kevin Pillar TOR 129 25 -104
Shin-Soo Choo TEX 89 189 100
Manny Machado BAL 192 92 -100
Matt Davidson CHW 163 65 -98
Paul Goldschmidt ARI 98 191 93

As to how Carpenter pulled off this rebound after his abysmal start, we’ll begin by comparing his before and after May 16th stats, side-by-side.

Matt Carpenter: A Tale of Two Seasons

Metric ≤May 15 ≥May 16 Change
Metric ≤May 15 ≥May 16 Change
BABIP 0.178 0.398 0.220
wOBA 0.255 0.462 0.207
xwOBA 0.371 0.448 0.077
SLG 0.272 0.691 0.419
xSLG 0.479 0.679 0.200
K% 28.6% 21.5% -7.1%
BB% 16.4% 11.6% -4.8%

The first thing to acknowledge is that Carpenter was the recipient of some pretty unforgiving batted ball luck through mid-May. You can–and probably should–adjust his “expected” stats to factor in his subpar speed, but the point stands that Carpenter’s .178 BABIP and .116 xwOBA-wOBA gap weren’t going to sustain themselves forever. Regardless, the 77 and 200 point spikes in expected wOBA and slugging percentage aren’t nothing. Carpenter’s contact quality has legitimately improved as the season has progressed.

The bottom two rows indicate that Carpenter is both striking out and walking less. The latter would presumably be quite concerning for a hitter whose offensive production is heavily buttressed by a high walk rate, but such fears have been allayed by the benefits of Carpenter’s more aggressive approach. His lower non-contact wOBA (i.e. walks, hit-by-pitches, and strikeouts) is offset and then some by far better observed and expected numbers when ball does meet bat.

Matt Carpenter: Change in Contact vs. Non-Contact Productivity

Metric ≤May 15 ≥May 16 Change
Metric ≤May 15 ≥May 16 Change
Percentage of PAs ending in contact 55.0% 66.9% 11.9%
wOBAcon 0.257 0.575 0.318
xwOBAcon 0.469 0.554 0.085
Non-contact wOBA 0.253 0.226 -0.027

Not only is this decrease in non-contact wOBA mitigated by greater efficiency on contact, but Carpenter has also been making this contact with more frequency.

Much of this trend in favor of contact-based production can be attributed to Carpenter’s shifting plate discipline profile, namely, his increased aggressiveness on pitches inside the strike zone. Baseball Savant offers Statcast search queries that allow users to filter results based on what segment of the zone of a pitch was located in. Boxes 1-9 in the image below are categorized as “Pitches In Zone,” 11-19 are “Edges,” and 21-29 are “Pitches Out of Zone.”

Baseball Savant

I then divided Carpenter’s plate discipline numbers into those three sections.

Admittedly, that is a very messy series of gridlines and numbers at first glance. The paramount takeaway is that Carpenter has made what is arguably the single most ideal plate discipline adjustment: pitchers are attacking him in the zone a bit more and he is swinging at these strikes more often, all the while remaining just as selective against non-strikes. He is also swinging and missing less frequently on all three types of pitches and posting a higher xwOBA versus all three as well.

That may explain the heightened volume of contact for Carpenter, but not his improved efficiency on a per-batted-ball basis (in other words, his higher wOBA and xwOBA on contact).

There is no doubt that batted ball luck played a nonzero role in Carpenter’s early struggles, but there might be more to his his xwOBA-wOBA discrepancy than random chance that didn’t break his way. While it’s true that the collective MLB wOBA (.312) has been 17 points lower than the leaguewide expected wOBA (.329) this season, that difference balloons to 35 points against the shift but is just 15 points against all other defensive alignments. Needless to say, this makes perfect sense when you think about it. Bad luck isn’t to blame for the 100 mph rocket that was stopped on the right side of the infield: there were three fielders stationed there.

Last month, my colleague John LaRue conducted some great research looking into the effects of the shift on both the Cardinals’ offense as a whole and the individuals who form that lineup. At the time–John tabulated data through May 7th–Carpenter accounted for 59.4% of all shifts deployed against St. Louis batters, a figure that stands at 62.3% since then. From May 16th to now, Carpenter has faced the shift in 86.5% of his plate appearances, an uptick from the 81.3% to begin 2018.

Juxtapose his results when confronting the shift before and after May 16th.

Matt Carpenter: Performance by Shift Situation

Situation (Metric) ≤May 15 ≥May 16 Change
Situation (Metric) ≤May 15 ≥May 16 Change
Shift (wOBA) 0.241 0.489 0.248
No Shift (wOBA) 0.301 0.361 0.060
Shift (xwOBA) 0.356 0.454 0.098
No Shift (xwOBA) 0.426 0.403 -0.023
Shift (SLG) 0.271 0.579 0.308
No Shift (SLG) 0.278 0.627 0.349
Shift (xSLG) 0.453 0.718 0.265
No Shift (xSLG) 0.613 0.682 0.069

Over the season’s first six weeks, Carpenter was demonstrably worse against the shift. Fast forward to his recent tear and you will find that the reverse has been true. He has combatted the shift by...pulling the ball more? His pull percentage against the shift has risen from 41.3% to 45.9%. In and of itself, that isn’t a very significant change. What is noteworthy are the changes to Carpenter’s batted ball breakdown when he pulls the ball against the shift. Here is his line drive, groundball, and flyball composition in those situations.

Matt Carpenter: Pulling Against the Shift

Metric ≤May 15 ≥May 16 Change
Metric ≤May 15 ≥May 16 Change
LD% 38.5% 37.8% -0.7%
GB% 46.2% 33.3% -12.8%
FB% 15.4% 28.9% 13.5%
GB/FB Ratio 3.0 1.2 -1.8
Average Launch Angle 6.8 15.1 8.3

Carpenter has more than doubled his average launch angle and more than halved his groundball-to-flyball ratio.

You can’t hit into the shift if you hit the ball over it.

Even during his dry spell, Carpenter was still ripping the cover off the baseball to the tune of a .990 wOBA and .921 xwOBA when he circumvented the shift by lifting the ball instead.

If anything, Carpenter has been even more “unlucky” as of late on groundballs hit into the shift. The good news is that it simply hasn’t mattered as much now that his approach is more oriented towards pulling flyballs. There are fewer groundballs to become unlucky outs in the first place.

Although Matt Carpenter’s plate discipline prowess has historically been one of the strongest facets of his game, his past tendency to excessively take called strikes was the subject of much scorn. In the weeks since, Carpenter has remedied this by adopting a more aggressive approach for pitches in the strike zone without compromising his swing rate on pitches located elsewhere. Opposing teams were increasingly shifting him to death until he delivered a counterpunch, bypassing whatever tactful positioning infielders had in store with a response of more flyballs, and in turn more extra-base hits.

In conclusion, Matt Carpenter is a really good–dare I say elite?–hitter.

Yeah, he just might be elite at this whole “create runs for the local baseball squadron” thing. He has been for a while now.