Is BABIP Alone to Blame for Aaron Nola’s Struggles?

A few years ago, I was driving down I-95 just north of Philadelphia when my timing belt broke. I had been happily cruising along in the far left lane of a four-lane road when all of a sudden my dashboard lit up with icons I’d never seen before and, even more alarmingly, my gas pedal refused to tell my car to “Go.” Without any means of acceleration, I somehow navigated my way across four lanes of traffic to the shoulder where my suddenly useless car came to a final stop. It was confusing, frustrating, and a little bit scary. Although I’ve never pitched professionally, I’m struck by a sense that right now Aaron Nola might feel a bit like I did that evening on the side of the road.

Aaron Nola was absolutely cruising. Through his first twelve starts he had a 2.65 ERA which was backed up by peripherals so strong that his FIP (2.77) and xFIP (2.74) provided an extra boost of confidence that, yes, Nola was for real. Then, without any real warning whatsoever, it all fell apart.

For the sake of convenience, let’s call those first 12 starts Nola’s Good Stretch and the most recent five starts his Bad Stretch. Nola has given up more earned runs (27 ER) in his 18-inning Bad Stretch than he did in the entire 78 innings of his Good Stretch (23 ER). That is an intense decline in results and, as a result, the Phillies announced that Nola will skip his final start before the All-Star Break in an effort to give him time to right a path that’s gone horribly awry. But look at a few more numbers across his splits and you’ll notice something a bit curious:

A .515 BABIP?! Despite a ground-ball rate that’s now pushing towards 60%?! That has to regress, doesn’t it? Are Nola’s struggles merely the result of extremely poor batted-ball luck and an inflated home-run rate on fly balls? A combination of his xFIP and common sense tell us that regression in those two categories would certainly help make Nola’s numbers look better. Take a look at just how ridiculous his BABIP has been over the past month:

Common sense will also tell us that, yes, regression is inevitable and will provide the desired result of fewer base-runners allowed by Nola. There’s nothing sustainable about a .500-plus BABIP, but is that really all that’s gone wrong for Nola over the past month? If only. Not only are batters finding increased success when they make contact against Nola, they’re making contact at an increased rate:

More balls in play and a higher percentage of them going for hits is a gnarly combination. Unfortunately, there’s more to this increase in hits than mere bloops and dinks. The quality of contact against Nola has dramatically improved during the Bad Stretch. His rate of soft-contact induced (Soft%) has plummeted while Hard and Medium contact have increased correspondingly:

Yes, Nola has been the victim of his fair share of bloop hits and frustrating infield singles — you don’t get to a .515 BABIP without those — but he has also been hit harder during the Bad Stretch than he was when he looked like an emerging top-of-the-rotation star at the start of the season.

The other significant change which doesn’t show up in unsustainable BABIP or HR/FB rates has been with his strikeout and walk rates.

Given the rise in Contact% against Nola, it’s no surprise that his strikeout rate has cratered. What is less automatically intuitive is a simultaneous rise in walk rate, but we’ll get to the cause of that in a moment.

To summarize: batters are hitting Nola’s pitches harder, more frequently, and with more success while also striking out less and walking more. Or, more succinctly: everything is bad for Aaron Nola.

What’s the cause and what’s the fix? It’s a tricky question which I first tried to address after his third start during the Bad Stretch. There are no giant red flags. His velocity has been relatively steady. The movement on his pitches is within expected ranges. His release points have remained consistent. Eno Sarris recently took a look at Nola’s struggles and concluded that a bit less run on his sinker was leading Nola to leave the pitch over the middle of the plate. The good news is that in his most recent start, that missing inch of run on Nola’s sinker did return, but Sarris’ larger point of Nola not locating pitches the way we’ve grown to expect of him, remains the key.

When the Bad Stretch began, Nola had hit three batters over the entirety of his 155.2 major-league innings. On June 26th, he hit three batters in three innings and has hit four batters total across the entire Bad Stretch. Nola has succeeded at every stop along his baseball career due to his incredible ability to locate pitches — fastballs and breaking pitches alike — precisely where he wants them. And, yet, now he’s doing this with the bases loaded:

It’s hard to conjure a pitching outcome that sounds more far-fetched for Nola than hitting a batter with the bases loaded, but here we are. The pitcher known for his exceptional command of the zone is suddenly struggling to locate and it’s left him extraordinarily vulnerable on the mound to every bad outcome a pitcher can face, from hard contact to walks to hit batsmen.

If command is the problem, what’s the solution? Well, that’s the million dollar question, now isn’t it? It’s promising that there hasn’t been a discernible decline in Nola’s stuff, but a sudden evaporation of a pitcher’s signature trait must be unbearably frustrating. It’s the kind of struggle that lacks an easy fix. Given that Nola has demonstrated a consistent ability to command the zone throughout his career, there is no reason to expect it won’t return. Whether it’s a mental or mechanical tweak Nola needs to undergo, hopefully his extended All-Star Break will help him return to his dominant Good Stretch form.

It’s possible, in fact, that his breakthrough has already been achieved. In his most recent start, he gave up five runs in the second inning before finally inducing a ground out to get out of the inning. He then remained in the game for three more innings and retired all nine batters he faced while striking out six. Perhaps we’ve already witnessed the beginning of Aaron Nola’s return, but now we’ll have to wait until after the break to find out.