Pitcher Pop-Ups: Considering as a Total, and on Different Bases.
I wasn’t able to get this directly in one fell swoop, but I did reason my way to checking all the plausible candidates, and can report that these are the pitchers who have generated 20 or more infield fly balls1 this year
(1) Bailey Ober 24
(2) Chase Burns 21
(2) Keider Montero 21
(2) Parker Messick 21
(5) Bryan Woo 20
(5) Trevor Rogers 20
I try to repress that urge to search for statistical secrets to success. Narrow, idiosyncratic categories should reflect small correlations, if any. But this is a good group of pitchers. I do not expect pushback on the assertion that Burns, Messick, Woo and Rogers are more than average quality. With Montero, he might just be having a career year,2 but he has a 135 ERA+. Ober is the only one of these guys where I would cite style before talent.
But still, it’s not quite clear what we’re looking at in this list. There may be better categories to look at to gauge quality, and total infield pop-ups may just be being dragged behind and looking good as a result.
The group is fly ball-oriented but not expressly defined that. The MLB ratio of fly balls-to-ground balls this year is 1.07. Ober has a 0.73-1 ratio, making him one of ten pitchers with 70+ innings 0.73 or lower. Burns is at 0.81, Montero at 0.86, Woo at 0.88 and Rogers at 0.90. So 0.81-0.90 seems to be the typical case. Messick is at 1.20, potentially making his number of infield fly balls more impressive.3
Strikeouts and innings are also important to consider for their roles.
Ober: 58 SO, 77 IP (6.8 per 9)
Burns: 118 SO, 102 2/3 IP (10.3 per 9)
Montero: 70 SO, 100 2/3 IP (6.3 per 9)
Messick: 110 SO, 112 IP (8.8 per 9)
Woo: 109 SO, 110 1/3 IP (8.9 per 9)
Rogers: 77 SO, 96 2/3 IP (7.2 per 9)
The most important thing analytically is just to note the average strikeout rate (8.1), which is below the average starting pitcher’s rate (8.4). The fact is that the more strikeouts you have, the fewer balls will be put in play against you, and everything else being equal, the fewer infield pop-ups, too. In considering whether strikeout pitchers might have 20 pop-outs, I found that I had to use a higher threshold for other indications of their pop-ups and fly balls if they were to stand a chance.
Coincidentally or not, the pitchers form two tiers in terms of strikeouts (I suppose, with Burns being more than a strikeout-per-9 in front of everybody else, you could say they form three tiers). So because there are differences of a size worthy to be labeled tiers, if strikeouts are made equivalent, the high-strikeout guys will take the lead over the low-strikeout.
Notwithstanding Woo’s failure to carry over his previous results to 2026, if we were to rank or draft the pitchers, I have little doubt that everyone in tier 1 would go before everyone in tier 2, and also little doubt that Burns would be chosen first. However, this probably doesn’t indicate the incremental value of “real infield popouts” with strikeouts removed, it probably just indicates that strikeouts are a separator when they are as different as they are here between tier 1 and tier 2. But I suppose I would at least entertain the possibility that if a pitcher checks off both the strikeout4 and infield pop-up boxes, he’s potentially a special guy.
To be citing strikeouts as noise, and by extension to be implying that Ober’s position as #1 pop-up pitcher is a resulting artifact, seems to miss the much more important point that he got those pop-ups in only 77 innings. On a per-inning basis, his pop-up edge on Messick and Woo is sizeable, even enormous. He has pitched only 3.21 innings per pop-out, Messick 5.33 innings per po-pup.
Since we are now at about the 99-game mark, if you consult the data I provided for you above, an innings total that stands just a hair over the game total does not seem to really mark a high-inning pitcher. To the extent that total infield pop-outs is identifying good pitchers, then, I do not think this is because innings are driving the results, and pitchers with a lot of innings are good pitchers. As a group, these guys do not have a lot of innings. But undeniably innings do plays a role.
On its leaderboard,5 FanGraphs only represents infield fly balls as a percentage of total fly balls. This implicitly does adjust for strikeouts, then, but also counts ground balls as a non-event, thus rating the ability to get the ball in the air in the first place not a talent, but a stylistic difference that must be negated. In comparison to the other total pop-up leaders, Messick therefore is given extra credit for his higher GB/FB ratio.
Interestingly, depending on the minimum innings that one sets, the first few names using infield fly percentage come back very much the same as the list for most regular old pop-ups. With 70 innings as the minimum, the leaders are Ober (21.2%), Messick (18.7%) and Burns (18.4%). If we drop to 60 innings, Janson Junk (18.5%, 15 total IFFB) takes the third spot.
The rationale for using total fly balls as the denominator probably has more on its side than the other options, including ignoring events de facto by just using the total.6 But the problem is that, from a practical standpoint, if you go down the IFFB% list, even if minimum innings are set at a high number, the total number of fly balls can be so low that you are looking at a high percentage that isn’t reliable, and not someone who is really generating significantly more pop-ups than expected.
I’ll give some examples. Dylan Cease has a 17.1 IFFB%, rating him 4th among pitchers with at least 70 innings. But that comes from just 12 pop-ups, a total number which probably ranks him somewhere between 30th and 50th. In an abstract sense, maybe Cease’s infield pop-ups are indeed fourth most impressive, but can we have any confidence it will continue, based on such a small sample? With his 1.30 GB/FB and 13.5 SO/9, it’s not hard to understand why there aren’t a lot of balls in the air to work with in his data, and why he particularly brings this issue to the fore.
At 15.7%, Ohtani is 9th among pitchers with 70 innings in IFFB%. But he has only 11 pop-ups-against in 85 2/3 innings.7
Max Fried’s statistics probably speak more to how slowly pop-ups accumulate, and to the necessity of looking at a lot of innings before drawing conclusions about a pitcher, than about the particular danger of framing the number in terms of total fly balls. Fried’s 12.3% this year has him well over the MLB 10.1%, as well as in the top 20% of those who have pitched 60 innings. Additionally, it seems at first that the 12.3% represents an interesting trend for him, as it is over twice his rate from 2023-2025. But then you find he has only generated 7 pop-ups this year, and nothing about the whole thing seems particularly interesting.
On a per-inning basis, Fried’s rate this year would no doubt represent an even greater increase than his IFFB% indicates. With both his fly ball percentage in general up and his strikeouts down, he has given himself more chances for pop-ups this year, as well as getting more. But I keep coming back to that measly total of 7.
When using a period of years, infield fly balls are best standardized on at least some basis, pitchers differing so much in how much and when they have pitched (not to mention that raw infield fly balls are not an available category on the leaderboard). So I generated the longer lists using IFFB%, looking at pitchers with at least 350 innings from 2023 to the present time.8
The top 10:
(1) Justin Verlander 14.6
(2) Kyle Hendricks 13.3
(3) Lucas Giolito 13.2
(4) Bailey Ober 13.2
(5) Michael Wacha 13.1
(6) Freddy Peralta 13.0
(7) Taijuan Walker 12.9
(8) Bailey Falter 12.9
(9) Andrew Abbott 12.7
(10) Zack Wheeler 12.5
When Verlander heads a list, your natural inclination is to think that you have struck validity gold. But of course Verlander in his late career is not so easily understood, not such a clear brand. For the years in question, this was the Mets, second-stint-Astros, Giants Verlander.9 His ERA+ was a cumulative 101.
As maybe one of the three best pitchers of very recent times, there is unity in Wheeler anchoring a list after Verlander begins it. But after indulging that thought, we must return to reality and confess that the list of the top 10 overall is certainly not notable for its strength. What appear instead are fly ball pitchers, and even more, four-seam fastball pitchers. Interestingly, the median GB/FB ratio was 0.89, very close to the ratio of the pop-up leaders of 2026, and again putting them in the “fly ball” but not the “extreme fly ball” category.
The group at the other end, the pitchers with the lowest IFFB%, are more provocative. Cristopher Sanchez is lowest, at 5.1. As maybe the pitcher today who most pulverizes opponents with the ground ball weapon, the direction of this cue is ambiguous. But looking at the rest of the group, which have E.R.A.s ranging from 2.99 (Max Fried) to 4.64 (Bryce Elder), I would seize on their ground ball tendency more than their talent as the defining characteristic. Their ground ball trend is encapsulated by a median GB/FB ratio of 1.87, an extremely telling number, even for a group of just ten.
My takeaway, then, is that if you are an extreme ground ball pitcher, you almost never get infield pop-ups.10 Keep in mind that IFFB% already equivalizes based on balls in the air, so we are not merely observing that pitchers with the fewest fly balls against them also have the fewest pop-ups against them. The phenomenon instead probably represents that pop-ups have the highest launch angle, and they thus defy the default tendency of a ground ball when these pitchers are on the mound more than regular fly balls do. Within balls hit, a ground ball pitcher is by definition less likely to have a ball put in the air against him, but from there is also less likely to have a ball hit against him that reach heights.
Since pop-ups are very much a good thing, having them all but foreclosed is then a disadvantage in being a ground ball pitcher (albeit a tiny one). At the same time, it would seem to reflect well on the ground ball pitchers that they almost never make a big launch angle mistake. In the same way that a pop-up represents a gross mishit for a batter, it could be looked upon as a mistake for a pitcher, even though it gives a good result.11
A few pitchers in this top 10 are not classic ground ball pitchers. Where one draws the line is subjective, but this might be said about Brady Singer (1.33 GB/FB, 6.9 IFFB%), Zac Gallen (1.23 GB/FB, 6.4 IFFB%) and MacKenzie Gore (0.97 GB/FB, 7.0 IFFB%). Does this then represent a failure on Gore’s part, for instance, that he has gotten a low rate of pop-ups even though he has gotten fly balls? My guess is that, in any one case, this point on the grid is probably a fluke and not an indictment of the pitcher, but that in the aggregate, it might be significant, and the point theoretically is right. So that we could know for sure, GB/FB12 could be controlled for, and then IFFB% correlated with success.13
As defined by FanGraphs.
Do we talk about “career years” less with pitchers than with position players? I think we do. Probably because the issue of career years with pitchers is so muddled by injury and the likelihood of it. There is no real pitching career progression as such.
I say this because then they would seem to be not chiefly a matter of style. Messick’s above-average GB/FB ratio indicates his versatility. Inherent in all of my analysis, by the way, is the assumption that infield pop-ups are very positive events (in concert with the hitter being disgusted with himself, not hitting the ball at all as desired, not threatening the defense, etc.).
You can certainly argue that, by 2026 strikeout standards, Woo and Messick really don’t do that, though. The argument for them would have to be that generating a lot of pop-ups (or at least fly balls) is a style that makes a big strikeout rate hard to get, and if such a pitcher just holds his own in strikeouts, then he’s uncommonly good.
And the snub of regular old infield fly balls (not as a percentage) was why I had to work to come up with my custom list.
God knows, I am not an authoritarian, but my experience tells me that the people who have made these decisions usually have put a lot of thought into them, and they probably got it right.
Funny — I admit I originally wrote down Ohtani because I thought he had only 5 pop-ups-against. No, David, that was pop-ups as a batter. Talk about an Ohtani-specific pitfall. At least I wasn’t going crazy in making that error.
There were 101 qualifiers.
Plus one second-stint Tigers start.
I do realize that in my takeaway, I have reversed the “if” and the “then” from the pattern of the research. It’s a slight liberty. Then again, it’s pretty hard to find pitchers with higher GB/FB ratios than these. There is considerable overlap in the highest ground ball and lowest pop-up groups.
But it’s interesting that the data seem to say that you’re either a ground ball pitcher or you’re not. You would think even ground ball pitchers would be changing their approach often enough that IFFB% would not correlate so strongly with GB/FB ratio. You would think that sometimes ground ball pitchers would make pitches intended to produce pop-ups, and IFFB% would reflect good or bad pitching and not just style.
Or just the more often used straight GB%, which includes “line drives” in the pie, and thus is a de facto ratio of GB/(FB+LD).
You would probably want to look at different outcomes, too (e.g., SO%, exit velocity, BAbip). I don’t know that there would be a whole lot to take away from finding that pitchers who get a lot of infield pop-ups have good control. All of the good results go into an overall success measure, some of which can’t logically correlate with the pop-up skill.