Lance Lynn and Finding Relief in the Underlying Underlying Metrics

Lance Lynn was phenomenal in his ultimate begin earlier than the All-Star break, going seven innings, hanging out 11 batters, and permitting simply three baserunners. By recreation rating, his outing in opposition to Toronto was among the many prime 20 begins of the yr. However when you choose to deal with components solely inside a pitcher’s management — strikeouts, walks, and residential runs — it wasn’t even one of the best of Lynn’s season. By FIP, his most dominant efficiency was a 16-strikeout gem in opposition to the Mariners a couple of weeks prior. Over seven frames, he walked solely two and stored all the things within the ballpark. Much more spectacular, all however one among his strikeouts got here on a swing and miss, as Lynn collected 33 whiffs on the night, probably the most by any pitcher in a single outing this season. His 16 strikeouts have been additionally probably the most in a single recreation this yr; no different pitcher has topped 13.

Lynn has two extra double-digit strikeout video games this yr, one every in opposition to the Rays and the Twins. Solely eight different pitchers have 4 or extra double-digit strikeout video games, and solely 4 have a number of begins of seven-plus innings, double-digit strikeouts, two or fewer walks, and nil residence runs: Kevin Gausman, Zac Gallen, Logan Webb, and Pablo López. (The White Sox, being the 2023 White Sox, went on to lose all 4 contests, however that’s hardly a mirrored image of Lynn’s efforts on the mound.)

So why am I making an attempt to show that Lynn continues to be so good at what he does? As a result of the standard statistics haven’t been sort to him currently. Nobody has given up extra runs this season, and his 6.03 ERA is an unsightly reminder that unhealthy issues occur to good pitchers. His 4.81 FIP is decrease, however that isn’t saying a lot; his ERA ranks 63rd out of 64 certified starters, and his FIP ranks 54th. It’s simple to have a look at these numbers and assume Lynn’s age is beginning to present; he turned 36 in Might, and his common fastball velocity has been dropping for the previous 4 years. He’s a major candidate for age-related decline.

However when you look previous ERA and previous FIP, the numbers paint an image of a pitcher who stays as regular and dependable as ever. The distinction between Lynn’s ERA and FIP is the second-largest amongst certified starters, behind solely Brady Singer. The distinction between his FIP and xFIP can also be the second-largest, simply trailing Yusei Kikuchi. Consequently, the gulf between his ERA and xFIP is wider than a Little League umpire’s strike zone:

That is positively a very good signal, and whereas Lynn absolutely isn’t happy together with his efficiency to this point, at the least his xFIP is true according to his profession common. 4 years in the past, he had his greatest season by WAR (6.8) and earned down-ballot Cy Younger votes for the primary time; his xFIP was 3.85. Two years later, he was a Cy Younger finalist and got here 5 innings away from an ERA title; his xFIP was 3.82. This yr, his ERA is larger than Mariah Carey’s falsetto, and his Cy Younger likelihood is slim to none. However his xFIP is 3.74.

Then once more, xFIP has its limits. When a pitcher has a FIP larger than his xFIP, it tells you one factor and one factor solely: His residence run-to-fly ball ratio is above league common. HR/FB is extremely risky in a small pattern measurement, and xFIP operates beneath the idea that with time, it often regresses towards league common. To cite the FanGraphs glossary:

The variety of fly balls that go for residence runs may be very delicate to pattern measurement which means that over the course of a season, the variety of residence runs a pitcher permits could also be larger or decrease than their true expertise signifies. This isn’t to say pitchers aren’t chargeable for the house runs they did enable, however quite to say that if you wish to decide how effectively they pitched, xFIP will take away a few of these fluctuations in HR/FB% and gives you a greater concept.

I discover xFIP philosophically fascinating. For all intents and functions, it’s a model of FIP that makes use of fly balls as an enter as an alternative of residence runs. But in contrast to strikeouts, that are inherently good for a pitcher, and in contrast to walks, HBPs, and residential runs, that are inherently unhealthy, fly balls are too advanced for such a inflexible dichotomy. More often than not they’re good, however typically they’re very, very unhealthy, and a few pitchers enable the unhealthy sort greater than others. What xFIP presumes is that each one fly balls are created equal, and although this assumption is patently false, it’s a helpful metric nonetheless. Why? As a result of the objective of xFIP isn’t to replicate every particular person pitcher’s true skills, however to get rid of excessive outliers. It’s prepared to be somewhat bit incorrect about a whole lot of pitchers to keep away from being fully incorrect about anybody. It really works as a result of the variance within the true expertise of MLB pitchers is a lot smaller than the potential variance in HR/FB over a small pattern of innings.

To deliver this dialog again to Lynn: the gulf between his FIP and xFIP introduces a dilemma. His 20% HR/FB is unsustainable, and nobody would dispute that. The distinction between his FIP and xFIP rightfully flags his HR/FB as a large outlier, so he’s due for some critical regression. The large query, nonetheless, is simply how a lot regression to count on. It’s laborious to look at a man hand over 22 residence runs in 18 begins and never start to marvel if one thing is amiss, nevertheless it’s simply as laborious to look at Lynn’s dominant begins and assume something is incorrect in any respect. Has he turn into extra prone to residence runs, or has he merely been the sufferer of outstanding misfortune?

One strategy to reply this query is to extend the pattern measurement, which is able to assist decide if Lynn’s HR/FB is something greater than a half-season fluke. Because it seems, it was beneath league common in eight of his first 9 seasons. In 2022, it abruptly shot up, and this yr it’s solely gotten larger:

Over his final 64 begins relationship again to Might 2021, Lynn has given up about 400 fly balls. That’s the estimated quantity vital for HR/FB to stabilize. He has a 14.4% HR/FB in that point, which isn’t almost as dramatic as a 20% fee, nevertheless it’s nonetheless considerably larger than common. In distinction, his HR/FB was considerably decrease than common over his earlier pattern of 400 fly balls. With that in thoughts, it begins to appear to be we’re coping with a worrisome pattern as an alternative of a mere fluke. To make issues worse, his HR/FB has been steadily rising since 2021:

However not so quick. The troubling pattern all however disappears once you cut up his numbers between residence and the street. Lynn spent his first six seasons on the pitcher-friendly Busch Stadium. In that point, his 6.5% HR/FB at residence was elite, even for Busch Stadium requirements, however his 11.7% HR/FB on the street was proper round league common. Since he got here to the American League in 2018, his HR/FB ratio has been a wholesome 12.5%. When he joined the White Sox in 2021 and began taking part in at Assured Rake Fee Subject, a veritable residence run haven, his HR/FB at residence skyrocketed, nevertheless it was nonetheless par for the course on the street.

In different phrases, Lynn was higher than common at stopping residence runs in St. Louis, and he’s been worse than common on the South Facet of Chicago. On the street, nonetheless, his HR/FB has all the time hovered round league common — till this yr, anyway. That being the case, I’m not satisfied Lynn has been trending within the incorrect path for his final 400 fly balls. His residence run drawback this season is new this season, so it’s the numbers from this season that demand our consideration.

Take a peek on the variety of hard-hit fly balls Lynn is giving up this season. That is the sort of contact that accounts for the overwhelming majority (about 96%) of residence runs. Due to this fact, if a pitcher is giving up too many homers, there’s a very good probability he’s giving up too many hard-hit fly balls. However Lynn? Not a lot:

How about pulled hard-hit fly balls? Pulled flies account for 61% of residence runs, so if a pitcher abruptly begins permitting extra pull contact, it might clarify a rise in his HR/FB. As destiny would have it, Lynn is, actually, giving up extra pulled hard-hit fly balls this yr, however the distinction is slight:

Clearly, an abundance of pulled hard-hit fly balls isn’t the issue. As an alternative, the issue is that Lynn can’t catch a break. Of the 16 such balls he’s given up, 15 have left the park. That’s a 93.8% residence run fee, in comparison with the league common of 60%. It’s the same story on hard-hit fly balls up the center; he’s permitting residence runs at twice the typical fee. Given the league-average HR/FB on hard-hit balls pulled or up the center, Lynn would have allowed 9 fewer homers this yr, bringing his FIP down from 4.81 to three.68. That’s a large distinction.

One other fascinating wrinkle to the story is that Lynn’s residence run drawback has solely been a problem in opposition to left-handed batters and, extra particularly, solely in opposition to his fastballs. Towards righties, he has a superbly regular HR/FB ratio and a very good 3.26 xFIP. Versus left-handers, nonetheless, he has the very best HR/FB within the league, and 15 of the 16 residence runs he’s allowed have come on fastballs. The numbers are excessive in opposition to each his four-seamer and his cutter, nevertheless it’s the previous taking the brunt of the influence:

Even stranger nonetheless, Lynn’s four-seam fastball has been downright nasty in opposition to right-handed hitters. Righties have a .196 wOBA, a .216 xwOBA, and a 40.4% whiff fee in opposition to it; it’s been his greatest put-away pitch in opposition to same-handed hitters, and he’s hanging them out at his highest fee in years. There aren’t any vital variations in his fastball’s motion profile or his launch level, and his velocity is just down by half a mile per hour. Neither Stuff+ nor PitchingBot thinks his fastball is any worse this yr than final. Thus, whereas the hyper-specificity of Lynn’s residence run troubles might level to a really peculiar drawback, it might additionally point out that is one massive fluke. In any case, if one thing actually wasn’t proper, wouldn’t you count on a pair extra signs to point out up?

When a pitcher can’t cease bleeding runs, it’s pure to presume he’s doing one thing incorrect. But for Lynn, his 3.74 xFIP is a brilliant mild on the finish of the tunnel. As terrible as all the house runs look, there’s no deeper indication that something is significantly incorrect. Lynn’s FIP is dreary, and his ERA is grim, however fortunately, there’s aid within the underlying metric’s underlying metric. He ought to be simply tremendous.