How Should the Dodgers Use Ross Stripling?

The “problems” the Los Angeles Dodgers face must seem foreign to most other major league teams. When Dave Roberts discussed his Opening Day rotation last weekend, it wasn’t in the same way most managers do. You know that way, because your favorite team’s manager probably does it. “Here are three good starters, one starter who we hope is good, and one starter who we hope is decent.” Not every team takes this approach, of course, but the league isn’t awash in great fourth starters, never mind fifth starters.

But the Dodgers aren’t the league. Their top three — Clayton Kershaw, Walker Buehler, and David Price — are locks. The team is using Julio Urías, who has bounced between starting and relieving, in the rotation. And Alex Wood, who was an above-average pitcher each of his last two years in Los Angeles before injuries ruined his 2019, is overqualified as a fifth starter.

It doesn’t stop there; the next four starters are all interesting as well. Dustin May, who might have made the rotation decision tougher for Roberts if he weren’t injured, is a top 15 prospect in all of baseball. Jimmy Nelson may not pitch, but if he does, he’s potentially excellent. Tony Gonsolin filled in last year in the rotation when the team faced injury issues and acquitted himself well.

All those guys are great options for a fifth starter, never mind a sixth or eighth. But to me, the Dodgers’ most interesting option for the back of the rotation isn’t any of those guys; it’s Ross Stripling. Stripling, you’ll recall, isn’t supposed to be on the team. They traded him, along with Joc Pederson and Andy Pages, to the Angels as a secondary move surrounding the Mookie Betts deal. But when the Betts trade stalled out and had to be reworked, Arte Moreno nixed the deal, sending Stripling and Pederson back to Chavez Ravine.

It’s clear, given that debacle, that the team was willing to enter 2020 without Stripling. But now that he’s staying, he presents an interesting puzzle. Is he what his stats say he is — a pitcher who has been comfortably above average as a starter and excellent as a reliever? And if he is, how should the Dodgers deploy him?

Let’s take these questions in order. First, how does he get to his excellent numbers? When Stripling came into the league, he threw roughly 50% fastballs. He complemented that with a curve and a slider that he threw with roughly even frequency, as well as a fringy changeup that he used instead of the slider against lefties.

That two breaking ball game is a relative rarity. In 2016, his debut year, only nine of the 144 pitchers who threw at least 100 innings used two breaking balls 15% of the time each or more. In 2019, that number grew to 13 out of 130; it’s still an uncommon mix.

Stripling himself is only barely still a member of that club. After initially leaning more heavily on the slider, he reversed course in 2019 to focus more on his curveball:

Stripling’s Pitch Mix By Year
2016 42.6% 3.9% 21.9% 21.6% 10.0%
2017 38.4% 0.0% 20.4% 34.7% 6.5%
2018 41.1% 0.1% 21.7% 26.2% 11.0%
2019 37.3% 1.7% 28.5% 17.7% 14.8%

Why lean more on the curveball? I could give you the theory behind it: his curveball and fastball break in nearly opposite directions. It’s not quite true spin axis mirroring, because his curveball features a good deal of gyroscopic spin, but all else equal, you’d like to see a fastball go straight up and a curveball straight down to maximally confuse hitters. Stripling’s curve complements his fastball that way, particularly now that he throws the fastball up in the zone. Even as his repertoire has varied over the years, the movement offset has been consistent:

Fastball/Breaking Ball Separation
Year Curve Separation (deg) Slider Separation (deg)
2016 161.8 56
2017 177.3 40.9
2018 168 46.9
2019 170.5 51
Measured by angle of movement (less gravity) per Statcast for FF, CU, SL

That’s not to say that there’s no use for the slider, which Stripling refers to as a cutter. It’s a useful pitch against righties, starting in a similar location to his fastball and breaking away from their bats. It also keeps hitters from sitting fastball/curveball; with a third pitch in the mix, guessing becomes significantly harder, particularly given that the slider is the only pitch that Stripling generally uses on the outside half of the plate.

Perhaps you’re skeptical that his curveball mirroring is all that valuable. Stripling, after all, developed the slider/cutter specifically to give batters another look. But consider this: Stripling threw a curveball immediately following a fastball to the same batter 125 times in 2019. Batters whiffed on 25 of them, a 20% swinging strike rate, out of their 57 swings. That means that they whiffed on a massive 43.9% of swings at curveballs that followed fastballs.

When he threw the curve any other way (to start a plate appearance or following any pitch other than a four-seam fastball), he generated 12.5% swinging strikes and whiffs on 29% of swings. The stacking combination of fastball into curve generated a ton of value.

Likewise, when Stripling followed the curve with a four-seamer, the fastball looked better. On curve-following heaters, he generated a 10.7% swinging strike rate and 20.5% whiffs per swing, as compared to 5.7% and 14.9%, respectively, for every other four-seam fastball.

None of this analysis says that Stripling should abandon his slider, or that his curveball is the perfect pitch for him. But it does suggest that he can make both the fastball and curveball better by playing them off one another. The slider, meanwhile, is relatively neutral; batters hit it well in a small sample when he threw it after a curveball, but otherwise did about the same no matter the sequencing.

What’s the point of all this analysis? To me, it says that Stripling is a good bet to continue his recent form. It’s not all smoke and mirrors; he has a strategy that works, and he’s leaning into it by throwing more curves. There may even be room for more fastballs and more curves, given his excellent results when pairing the two.

The slider and changeup are palate cleansers; they keep batters from seeing the two main attractions too often, and because they’re so separated in movement and location from the fastball and curveball, batters can’t guess wrong and get bailed out with a small adjustment. They’re useful, but only as secondary attractions.

Of course, the fact that Stripling has two well-paired pitches ties into the way the Dodgers have used him. Two-pitch pitchers are often best as relievers, and the Dodgers have used Stripling as a reliever frequently; he’s thrown 130 innings of relief and 257 innings as a starter in his career.

Even if we assume that Stripling is a solid starter, his value to the Dodgers depends on their other options. With Urías, Wood, May, and Gonsolin all there to soak up innings, Stripling’s WARD (wins above replacement Dodger) isn’t particularly high. Could his best value to the team really be as a high-leverage reliever?

My first instinct is to say no. After all, good pitchers are generally more valuable as starters, and Stripling certainly qualifies as a good pitcher. But on the Dodgers specifically, I can see the case for a swingman or relief role.

There’s almost no world where Stripling accrues more WAR as a reliever than a starter. But as I mentioned above, WAR isn’t the right metric for the Dodgers. Not only do they have a bevy of other starters who could accrue positive WAR, but a win or two above replacement is more or less meaningless to them. Do they want to win 106 games instead of 104? Do they want to eliminate the Padres from the NL West race on September 7th rather than 11th?

On the other hand, come playoff time, Stripling will likely provide the most value out of the bullpen. Barring any injuries, there’s only one spot for Wood, Urías, May, Gonsolin, and Stripling. As good as Stripling is, he’s likely not a huge upgrade over anyone else in that pack. And if he can’t be a huge upgrade there, he can be in the bullpen.

With the starting rotation packed with lefties, teams will be ready with a raftful of left-handers available to pinch hit when righty relievers come in. In past years, this has been a problem for the Dodgers; they’ve improvised the left-handed bullpen role by using Urías and Wood at times, but unless Scott Alexander and Adam Kolarek excite you enough that you’d like to see them despite the new three-batter minimum, there’s not that much in the pipeline for everyday lefty relievers.

Luckily, Stripling can do a decent approximation of a LOOGY. He has a sizable reverse platoon split for his career, allowing a 14% lower wOBA to lefties than righties. Even after regressing that to the mean based on his total batters faced, it comes out to a 5% wOBA advantage against opposite-handed batters. That generally tracks with his stuff — righties with good changeups do well against lefties, as do pitchers whose stuff breaks more North/South than East/West. Stripling has a good enough changeup to qualify, and the fastball and curveball are pretty close to exactly straight up and straight down.

In addition to that, there’s value in certainty. Stripling’s wOBA allowed is 8% lower as a reliever than as a starter, right in line with the long-term average for pitchers who switch between the two roles. He’s not learning a new skill for the first time; he knows exactly what he’s doing out of the pen. He throws his fastball 1.1 mph harder as a reliever, and for someone living in the low 90s, that extra tick makes a difference. Finally, with no second time through the order to worry about, he could lean on the curveball more often — in his relief-heaviest year, 2017, he still featured the slider, so we haven’t seen a curves-and-heat Stripling in relief yet.

In the past, the Dodgers used Kenta Maeda in a fireman role. It’s not quite the same fit — Maeda had a massive positive platoon split, and the Dodgers got him better matchups by using him out of the bullpen. But Stripling, like Maeda, uses extra velocity to good effect — in his career, he’s generated a 16.9% whiff rate on fastballs below 92mph and 22.5% above 92 mph.

Additionally, he’s capable of pitching several innings of relief; he’s gone longer than an inning in 46 of his 84 career relief outings. For a bullpen that might feature the stylings of Joe Kelly in high leverage roles if they’re not careful, getting some length out of a quality pitcher is a nice bonus.

Ross Stripling is terribly miscast on the Dodgers. He’s a solid number three starter, or even a number two in a pinch, almost anywhere else in the league. The curveball plays, the fastball has enough movement that batters have a tough time with it despite its middling velocity, and his command ties the whole package together. Among pitchers with 200 IP over the last two years, he’s 27th in strikeout rate at 26.2%, just behind Luis Castillo and ahead of Price and Kershaw. He barely walks anyone — his 21.4% K-BB rate is an even more impressive 17th.

Stripling is good enough to excel wherever the team uses him. But on this team, I think that role might be out of the bullpen. It’s not fair to Stripling, who looked like potentially the best pitcher in a thin Angels rotation. But short of trading him, the Dodgers could get the most utility out of him by bringing him in from the bullpen to kill rallies and rescue ailing starters. It’s not exciting, but it’s pragmatic, and for a team that already has everything, pragmatism is the order of the day.

Ben is a writer at FanGraphs. He can be found on Twitter @_Ben_Clemens.

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4 years ago

I love Stripling as much as anybody, but he doesn’t seem to have much stamina. He’s said himself that he ran out of gas in 2018 and seemed to be a little dinged up in 2019.