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Getting Zack Wheeler’s stats to match his stuff

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What the team might be checking out to help the Phils’ new “1A” take the next step

Atlanta Braves v New York Mets Photo by Rich Schultz/Getty Images

This is how Zack Wheeler’s Phillies tenure is going to be defined: How close will he come to fulfilling the Gerrit Cole comps already being heaped upon him?

It’s a huge ask, and dramatically ramps up expectations for a guy many were already looking toward to be Aaron Nola’s co-anchor once he signed for comfortably more than nine figures. Not only is this guy supposed to be good, he’s got the chance of turning into one of the game’s three or four most-dominant starters from the past two seasons?

Bonne chance.

But if this is how we’re going to view Wheeler, it’s at least worth a little effort to try and figure out exactly how the team might try and turn him into The Next Cole, or something resembling that. There has to be some sort of fire attached to all this smoke, right?

As pointed out in Andrew Simon’s article linked above, we’re greeted with this very thing on Wheeler’s BaseballSavant page, in the Statcast tab:


Cool, so we’re starting things off with a bang. Although, it’s worth pointing out that while the velo and movement measurements stack up, their pitches’ respective pitch spin rates most certainly do not, so we see how pitch appearances can be similar while their compositions can ultimately differ.

Spin (RPM)

Pitcher 4FB Spin CB Spin SL Spin CH Spin
Pitcher 4FB Spin CB Spin SL Spin CH Spin
Cole 2,530 2,901 2,622 1,870
Wheeler 2,341 2,647 2,386 1,771

The exact nature of Astros pitchers’ bumps in spin notwithstanding, it’s going to take a little bit more to make a convincing argument that Wheeler’s truly got similar stuff to Cole, though it’s nice to see that Wheeler is at least in the neighborhood. What becomes confusing is this: If Wheeler’s raw stuff (in velo and movement, anyway) profiles so similarly to one of the game’s premier talents, why have his results not kept pace?

Wheeler’s batted ball profile and comps

Leaving aside Bassitt, Bundy, Erlin, and the late Skaggs and focusing on the highest comps in the image above, we have two pitchers with pretty significantly disparate stuff whose batted ball profiles most closely align with Wheeler’s: Free agent Homer Bailey and the Cubs’ Kyle Hendricks. Bailey’s fastball averages 93-94 T97, while Hendricks usually tops out around 90-91. Yet their batted ball results were very similar in 2019. If nothing else, this would appear to be a small point in favor of the thought that it’s not what you have, necessarily, but how you use it.

Which brings us back to Wheeler. How can a pitcher with Cole Stuff get more Cole-like Results, instead of Bailey-like Results?

There’s a thought that elevating more fastballs is the way to go, especially with a heater that steams as much as Wheeler’s does. It’s harder to catch up to, and even harder to square up, the higher you go in the zone. Swings are tailored to do damage in the strike zone between the thighs and chest; not the shoulders.

So when Wheeler took that path last year, he found some success. Looking at fastballs elevated in the zone or above it (see the picture below), we find that Wheeler allowed a .274 opponents’ SLG and just 13 batted balls with an exit velocity of 90 MPH or harder in 33 total batted ball events (39 percent).


The .274 SLG is good; only 29 of 157 pitchers with 50-plus high heaters had a lower one, a group of 29 that includes Cole. And those 13 90-plus EV batted balls comprise an almost infinitesimally small portion of his total offerings last year in a virtual tie with pitchers both similar and dissimilar. See below. Chances are, Jason Vargas wasn’t challenging hitters with elevated 86 MPH cheese all that often.


And that last part is key: Frequency. We mention Cole as someone who limited SLG on high fastballs. He and Wheeler share some real estate there, being among the 30 or so best in the league last year at limiting damage on those pitches. Where things begin to diverge is in how often they visited that part of or near the zone. Wheeler only threw 441 pitches in those zones (14 percent of his season total), while Cole more than doubled him with 1,009 high fastballs (30 percent). With that as a weighting component, Cole’s performance surges ahead that much more.

So the next question is somewhat obvious: Can Wheeler find similar success by climbing the ladder more in 2020?

Let’s focus only on pitches above the zone for a moment. With a little extra height, these pitches are even tougher to square up, but run the risk of the hitter immediately seeing it as too high, or having the release fractionally delayed just enough to cause it to sit squarely in the nitro zone. Kinda like this Juan Soto upper tank job.

For Cole, 576 of his 1,009 elevated fastballs ended up out of the zone (spots 11 and 12 in the key from earlier in this post). Of those, 107 (or 18.6 percent) resulted in a swing and miss. Wheeler, on the other hand, went to the higher rent district 256 times in 441 elevated chances — a higher rate — but had just 30 whiffs (11.7 percent). Things get no better in the zone (spots 1, 2, and 3 from the above legend), as Cole got 146 whiffs in 433 pitches (33.7 percent) while Wheeler had just 40 in 185 (21.6 percent), an indicator that Cole’s stuff was even more unhittable despite being in more competitive spots. A good measure of a pitcher’s nastiness is measuring hitters’ inability to do anything with it, even if it’s a strike.

Again we come back to the gulf between stuff and performance. If these two have such similar offerings in both velocity and movement, why is one pitcher generating so many more favorable outcomes?

While he may never quite reach Cole levels of effectiveness, it seems important for Wheeler to increase the amount of high fastballs he throws after all. If he’s able to sustain the effectiveness his heater showed it could have in 2019 — and sequencing would play an important part in making sure he stays balanced — then it seems worthwhile to dip into that well more frequently.

There’s another thing that Wheeler may not have done as frequently as he should have, too: Throw his curveball. It was, by most Statcast measures, his most dominant pitch last year, but one he only threw 10 percent of the time.


(The splitter and change are essentially the same pitch, but are broken out above)

He’s thrown the curve less and less since his 2017 return from injury, but it’s never seemed to grade out as anything other than a plus pitch. Part of the problem could be a hesitance to use the pitch in non-putaway counts.


Its presence is predominantly featured in two-strike counts, but almost never shows up when he falls behind. It’s one less pitch hitters have had to think about, and flips the script for Wheeler’s fastballs and sliders.

Wheeler Opponents’ SLG and Whiff% (2019)

Count Fastball SLG Whiff% Slider SLG Whiff% Change/Split SLG Whiff%
Count Fastball SLG Whiff% Slider SLG Whiff% Change/Split SLG Whiff%
Pitcher Ahead .347 12.6% (70/554) .177 12.1% (26/215) .422 18.0% (22/122)
Batter Ahead .535 12.2% (60/491) .400 18.7% (23/123) .421 12.7% (10/79)
Even .423 9.3% (76/819) .533 11.2% (32/287) .289 8.5% (13/153)

A couple things stand out to me from the table above.

  1. Wheeler very, very frequently went to the slider in even counts. This lumps 0-0, 1-1, and 2-2 together, though more of his 1-1 pitches were sliders than 2-2
  2. The changeup having such a low SLG in even counts makes me think it was well-called and was often successful at keeping hitters off-balance
  3. The whiff rates are an encouraging offset, but it’s clear hitters had more success against the fastball and slider when they held the advantage

Which brings us to our third point.

It doesn’t seem to be a stretch to think that Wheeler is at his best when working ahead in the count, and hitters have clearly clued in to that. Check out the rise in first-pitch swings (1st%) year-over-year, and how they dwarf both his career rates and the league averages over that time (the bottom two rows).

Pitch Summary -- Pitching *
Year Age Tm PA Str% L/Str S/Str Con 1st%
2017 27 NYM 387 63.0% 26.4% 16.3% 77.8% 60.7%
2018 28 NYM 745 65.6% 25.0% 18.5% 75.3% 62.0%
2019 29 NYM 828 67.1% 24.2% 17.4% 77.0% 65.8%
5 Yr 5 Yr 5 Yr 3187 64.0% 25.9% 17.5% 76.4% 59.6%
MLB MLB MLB 63.8% 26.7% 17.4% 76.3% 60.4%
Provided by View Original Table
Generated 12/17/2019.

This could be a good justification for more first-pitch changeups, something Wheeler started doing way more of last season: He threw 73 first-pitch changeups in 2019 (after throwing 65 in 2018 and just 14 in 2017), one of which Ketel Marte hit for a homer, but otherwise looked to be emblematic of a pretty effective strategy adjustment.

Even absent an uptick in spin, there looks to be a path for Wheeler to continue to build upon last year’s performance. More elevation with the fastball, a few more curveballs sprinkled in, and unleashing the changeup to get ahead early in counts (especially in second and third PAs for the same hitter) look like three ingredients for, ahem, continued success. We’ll see what other ideas the team has for building a winning program for Zack.