FanGraphs Weekly Mailbag: August 15, 2026

I made my first trip to Oracle Park earlier this week to catch the final two games of a three-game set between the Giants and Astros. I was in San Francisco reporting a different story, but I was eager talk about Yordan Alvarez with his teammates, his opponents, and pretty much anybody else who was interested. I’ve long compared him to Willie McCovey because of his overwhelming physical stature and profile at the plate — it helps that Alvarez, like McCovey, also bats left-handed and wears no. 44 — and I considered myself fortunate to get to see the Astros DH play in San Francisco. I hoped I’d get to witness him launch one into McCovey Cove. That didn’t happen, but it was still fun to watch him during what’s turning into a career year.

One of the players I talked to about Alvarez was Houston outfielder Taylor Trammell. His response, to a question about what makes Alvarez so good, is worth sharing. “He is the most efficient player I’ve ever seen,” Trammell said. “He does exactly what he needs to do to get himself ready to play well, and then does nothing more. His preparation seems so effortless because he has so much confidence in his routine. He’s shrunken it all into a box.” Trammell also bats left-handed, yet he said he can’t study Alvarez to figure out what to do in the box because “pitchers throw differently to him. They throw him the pitches they don’t throw to anyone else just to try something to get him out.” He said Alvarez sees changeups from pitchers that he didn’t even know had changeups, and while that might’ve been a slight exaggeration, it worked to explain the helplessness that opposing pitchers must feel when Alvarez is in the box.

That’s the last we’ll discuss Alvarez here today, but if you want to read more about his MVP-worthy season, I’d encourage you to check out Dan Szymborski’s post from Monday breaking down Alvarez’s odds of winning the American League Triple Crown. Instead, in this week’s mailbag, we’re answering your questions about a pair of Cardinals pitchers who are greatly outperforming their peripherals, whether strong plate discipline translates to successful ABS challenges, the final franchise to (maybe) register a 100-loss season, and more. But first, I’d like to remind you that this mailbag is exclusive to FanGraphs Members. If you aren’t yet a Member and would like to keep reading, you can sign up for a Membership here. It’s the best way to both experience the site and support our staff, and it comes with a bunch of other great benefits. Also, if you’d like to ask a question for an upcoming mailbag, send me an email at [email protected].

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How do you explain Kyle Leahy and Michael McGreevy outperforming their xERA by 1.5-2 runs at this point in the season? Are they just running extremely hot with batted-ball luck, or is there something more interesting going on? — Spenser

Ahhh yes, Cardinals pitchers outperforming their peripherals. We’ve seen this before. Think Adam Wainwright, Dakota Hudson, and Kwang Hyun Kim, among others in recent years. Some of this is an organizational approach. The Cardinals have long placed a premium on strong up-the-middle defense, and that goes a long way toward turning batted balls into outs. Some of their pitchers’ overperformance comes from luck, but at some point, it starts to shift from luck to true ability. Maybe that ability is an overdependence on defensive performance, which ultimately is not something a pitcher can control, but it is an ability nonetheless. Basically, if you have a strong defense behind you, you might as well take advantage of it.

In broad strokes, this is true for both Leahy and McGreevy, as well as, to a lesser extent, Andre Pallante, Hunter Dobbins, and closer Riley O’Brien. But here’s the interesting thing: Both Leahy and McGreevy are significant overperformers when it comes to ERA and xERA, but the gap is far less wide between their ERA and FIP:

This is also true for the collective St. Louis pitching staff:

So what’s going on? To answer that, we should first review the difference between xERA and FIP. Expected ERA accounts for both the quantity of contact a pitcher allows and the quality of that contact (exit velocity and launch angle), though crucially, it doesn’t factor in batted-ball direction. According to its MLB Glossary definition, its purpose is “to credit the pitcher… for the moment of contact, not for what might happen to that contact thanks to other factors like ballpark, weather, or defense.” FIP, meanwhile, doesn’t account for contact quality; instead, it considers only the outcomes that a pitcher has complete control over: strikeouts, walks, hit-by-pitches, and home runs.

Let’s look under the hood at the two pitchers Spenser asked about, beginning with Leahy:

As you can see, Leahy has a below-average strikeout rate, but his walk rate and home run rate are both better than league average, helping to explain his low FIP. However, he allows a lot of hard contact. His 47.7% hard-hit rate ranks in the second percentile of all pitchers and his 10.2% barrel rate is in the 13th percentile, resulting in his 14th-percentile xERA. (Here, I should mention that our site puts Leahy’s xERA at 5.05, while Baseball Savant has it at 5.08.)

Relative to the league, though, Leahy is getting better results on hard contact. He’s allowing a .566 wOBA on hard contact this season, whereas the league-wide wOBA on hard contact is .609.

Some of this is probably due to luck, but I think there’s something else going on. Leahy is minimizing the damage of the hard contact he gives up by directing it away from the most harmful locations. Only 6.5% of the hard contact he allows results in pulled fly balls; the league average pulled fly ball rate on hard contact is 11.3%. Add in line drives, and Leahy’s pulled air rate on hard-hit balls climbs to 20.8%, five percentage points below the league average. Meanwhile, 22.0% of the hard contact he allows results in a pulled groundball, compared to the league’s mark of 18.5%.

That’s important because hard-hit pulled fly balls are by far the most impactful form of contact a batter can make. League-wide, batters are running a 1.385 wOBA on hard-hit pulled fly balls and a .805 wOBA on hard-hit pulled line drives, but on hard-hit pulled grounders, their wOBA is .311.

Similarly, McGreevy is a low-strikeout, low-walk pitcher who gives up a ton of hard contact, but unlike Leahy, McGreevy is homer prone:

McGreevy’s 43.4% hard-hit rate allowed is lower than Leahy’s, but it’s still in just the 14th percentile, and his 10.4% barrel rate is slightly higher than Leahy’s. The real difference between the two hurlers is the direction of the hard contact they surrender. Of the hard contact McGreevy gives up, 12.2% results in pulled fly balls, and including line drives, his pulled air rate on hard contact is 23.8%. Only 16.9% of his hard-hit balls are pulled grounders.

Based on the data above, it would seem that Leahy’s overperformance is more sustainable than McGreevy’s, but I don’t think we can draw any strong conclusions. Four months of batted-ball data is hardly a robust sample. To provide some additional context, I reached out to Jeff Jones, who covers the Cardinals for the Belleville News-Democrat. Jeff agreed that McGreevy’s success has a lot to do with batted-ball luck and pitching in front of a strong defense. He told me that whenever he and the other beat writers ask the Cardinals about McGreevy’s outperforming his peripherals, the team cites his pitch mix and deception as reasons to believe he can keep it up, but that “historically, we have not gotten much in the way of a more compelling explanation than that.”

Leahy, though, is a more interesting case, for reasons beyond the directionality of his hard contact. His whiff rate, Jeff pointed out, has climbed throughout the season as he’s adjusted the usage of his pitches.

Since the beginning of May, Leahy has a 2.66 ERA, a 4.66 xERA, a 3.00 FIP, and a 3.60 xFIP across 17 starts and 88 innings. His whiff rate during that span is 22.8%, up from 20.3% prior to it. Using the start of May as the cutoff, he’s throwing fewer four-seamers and sinkers and way more curveballs and changeups:

Against left-handed hitters, he’s pretty much stopped throwing his sinker, replacing it with his changeup, while he’s also increased the use of his slider and sweeper; he still throws a lot of curveballs to lefties, but not nearly as many as he did before:

When facing righties, his pitch usage distribution is the same, in that from most frequent to least frequent his offerings are: sinker, slider, sweeper, four-seamer, curveball, changeup. However, he’s brought the usage rates of those pitches much closer together, making him more unpredictable:

So, is this just luck, or is there something else going on here? I’m skeptical about McGreevy. The longer he does it, the more faith I’ll have that he is doing something specific that’s allowing him to outperform his peripherals, and then perhaps this topic will be worth revisiting in order to figure out what that special thing is. But for now, I remain unconvinced. Leahy, on the other hand, appears to have made changes to his usage rates that are leading to more whiffs and could be helping him limit the damage of the hard contact he gives up.

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This probably isn’t that hard to answer, but I’m broadly curious about what traits are associated with successful challenges by hitters. I saw Andy Pages make a challenge the other day early in the game, and the announcers immediately winced at it. I think it failed.

Basically, are hitters who have good plate discipline stats (walk rates, in-zone swing rates, chase rates, etc.) also good at making challenges? Or are they actually distinct skill sets?

Might, all things equal, veterans be better at making challenges (being more sober-minded, ha) or are youngsters better (since they have more of their experience under ABS)? — Hayden

Michael Baumann: Well, Hayden, we’re about to find out how hard this is to answer, aren’t we?

Because we’ve got two questions here. First: Is plate discipline correlated to challenge success? Second: Is experience correlated to challenge success?

That seems simple enough, but we have to define plate discipline (you gave us a couple options here), experience, and challenge success. And there are plenty of choices for each. And what if those factors interact? Should this be a mixed-effect model? Should we attempt to find correlation on a player-by-player basis, or should we separate players into buckets?

All of a sudden I’m flashing back to grad school, and suffice it to say there’s a reason I’m a sportswriter now and not a social scientist.

Besides, I’m pretty agnostic on most of these questions. The one thing I’ll say for sure is that the raw run value for challenges is mostly a function of challenge frequency. Sal Stewart leads the league in challenge run value because he’s what basketball people would call a chucker. The other night, I threw a wadded up piece of paper at my office trash can and missed, and Sal Stewart poofed into existence and tapped his helmet at me.

So to measure the success of challenges, I’ll be using overturn rate and runs per review request, rather than the run total. There has to be some kind of penalty for challenging and getting it wrong.

I’ll also be sorting players into groups, rather than trying to regress and chart individual data points. So far this year, 631 players have batted in the majors, and the modal number of review requests among those hitters is zero. Only 136 hitters have 10 or more challenges, and only 280 hitters have five or more. That’s just not a big enough sample size.

This season, 489 hitters have challenged at least one call. I split them out into deciles based on six different stats. The first, to test the veteran-ness theory: Career plate appearances. This might not be a perfect fit, because good players rack up plate appearances quickly. For example: Junior Caminero, who just turned 23, is above the median career plate-appearance total. But getting up-to-the-day player age or MLB service time figures for this dataset wasn’t worth the effort, so here we are.

Experience doesn’t seem to have that big an effect on challenge rate or productivity for hitters. A lot of more experienced hitters — between the 61st and 90th percentile, which comes to roughly 1,700 career PA to 4,700 career PA — are actually slightly more conservative when it comes to challenging. The 80th percentile group (between 2,300 and 3,050 career PA, give or take) is the most efficient group of challengers, but the spread, both on success rate and runs per review, is tiny.

The next stat I tested was wRC+, because I figured it was worth looking into whether there was a connection between challenge success and whether a hitter is any good or not.

And there is, but it turns out bad hitters make good challengers. That bottom decile comprises truly awful hitters: We’re talking guys with a wRC+ of 50 or less this year. And yet their success rate is the highest of any wRC+ decile, and their runs per challenge rate is tied for the best out of any of the 60 slices I took across any stat. Not having a hypothesis for why this might be the case, I’m inclined to chalk it up to noise. Especially because the top 80% of the population — wRC+ of 70 or better — is pretty similar across the board.

On to swing rate…

Now we’re getting somewhere. It’s not a perfect sliding scale, but generally speaking, aggressive hitters challenge less frequently and are less successful when they do.

That might have something to do with top-down directives. Just as a team’s cleanup hitter might have a standing green light in a 3-0 count, while the rookie shortstop in the nine-hole would get benched for taking the bat off his shoulder, it stands to reason that a manager would trust his more selective hitters to pick their spots. On top of that, the hitters’ freedom to challenge varies as much from team to team as it does player to player. As in all things, some clubs are more aggressive about challenges, others more conservative.

You can see swing rate effects in the overall swing rate, but it stands out most in chase rate. When it comes to in-zone swing rate, the challenge numbers don’t correlate as cleanly.

Again, that makes sense; Z-Swing% isn’t actually a very good measure of plate discipline. No hitter wants to swing at pitches outside the strike zone, but that doesn’t mean all strikes are hittable. The bottom 25 players in Z-Swing% include a few guys with a reputation for passivity, but it also includes James Wood, Alex Bregman, Seiya Suzuki, Mike Trout, and Yordan Alvarez. These players know the strike zone as well as anyone, but they have the ability to distinguish between a pitch in the zone and a pitch they can do damage on. So they end up taking a lot of called strikes, in the hope of getting something better to hit later in the plate appearance.

There are exceptions. Ernie Clement swings at everything, and he’s 7-for-12 on challenges this year. Cal Raleigh and CJ Abrams are two of the most efficient high-volume challengers in the league, and both of them have chase rates in the high 30s. Wood and Matt Olson, both highly selective power hitters, have been godawful at challenges — both in being successful and in picking their spots. But in general, a lower chase rate suggests a greater ability to challenge strike calls successfully.

The last stat I checked was walk rate. When I talk about plate discipline, I often default to walk rate as a catch-all stat. It’s not as precise as the various swing rate metrics, but those figures often say more about approach than a hitter’s ability to determine the frontiers of the strike zone. Sometimes it’s better to just dumb things down.

Challenge success rate doesn’t map perfectly with walk rate, though it should be noted that there’s a step change in challenge success rate around the 30th percentile here. (That’s around the 7% walk rate range.)

Still, runs gained per review goes up with each walk rate bucket, so much so that you can see that trend on a line graph.

That’s exciting! As a heat check, I decided to graph individual hitters with at least 10 challenges this year, in the hope that this trend would still be noticeable on an individual basis.

OK, that didn’t go as well as I’d hoped. Still, the line goes up and to the right.

Anyways, Hayden, if you’re still in there under all these tables and graphs, it looks like experience or veteran-ness (veteranity?) doesn’t meaningfully predict challenge success. Neither does overall hitter performance.

But chase rate and walk rate do. Stats that indicate command of the strike zone correlate to success in a game-within-a-game that hinges on command of the strike zone. Who could’ve predicted that?

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Hi FanGraphs!

I read somewhere recently that there’s only one active franchise that’s never fielded a 100-loss team. It’s the Angels, of all teams! Not to be a party pooper, but what are the chances that will change this year?

— Yer Main Guy

Davy Andrews: Well, Main Guy, as I write this on Thursday afternoon, the Angels are indeed on pace for exactly 100 losses, and they just got worse at the deadline. However, our projected standings see them ending up with 65 wins and 97 losses. PECOTA projects 98.4 losses (and it’s always impressive to lose a fraction of a game). ZiPS also sees them winning a hair over 98 games. The reason these projection systems are (relatively speaking, of course) more sanguine about the bloodless Angels is that they’ll have an easier go of it down the stretch. The teams they’ve faced so far have a winning percentage of .497, a bit easier than the average team. But their remaining schedule is at .487, the eighth-easiest mark in the game.

But I’m not really answering your question here. You asked for the chances that they make it to 100 losses, and I know a guy who can help. Dan Szymborski generously ran the rest of the season through ZiPS. ZiPS gives the Angels a 60.4% chance of reaching 63 wins, which means it gives them a 39.6% chance of losing 100 games. Let’s round to 40%, because we are not capable of processing the difference between 39.6% and 40% anyway.

Still, there’s plenty of reason to hope they’ll get there. Three more losses definitely seems like it’s within the margin for error, and there’s still plenty of time.

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I was a little surprised to read that Jim Palmer faced 870 different hitters in his career. I would have thought it was more. I guess there were fewer teams and maybe less roster turnover when he was playing.

It got me wondering. What pitcher has faced the most hitters and what hitter has faced the most pitchers? — Michael

Jon Becker: Hello there Michael! You’re right that fewer teams, smaller rosters, the lack of interleague play, and less frequent team-switching made for less variety in the number of unique batters pitchers faced, and vice versa. Spending his entire career with one team in one league gave Palmer a relatively less diverse group of opponents compared to the top of the list.

Here are the top 20 pitchers in major league history by most unique batters faced, with an obvious skew toward recent pitchers with long careers:

Only Wainwright and Kershaw were one-team pitchers, but both lasted long enough to play into the era of scheduling wherein every team faced every other team at least every other season. The pitchers whose careers ended earlier — namely John and Ryan — benefitted from extraordinarily long careers on a variety of teams across both leagues.

As for the batters who faced the most pitchers:

Half of the players on this list have at least one major league plate appearance this year, with the more balanced schedule turbocharging the impact on facing unique arms. Of course, teams also use more pitchers within games than they used to; a batter may face four different pitchers in five plate appearances in a given game, for example. Teams are also using more pitchers within given seasons. When a player faces the same team later in the season, he may face an entirely different set of arms.

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