Two Exciting Rookies and One Big Problem

On Saturday, Sal Stewart hit his 30th HR and Sarah Langs pulled yet another fun stat:

Sal Stewart is the 14th rookie in MLB history with 30+ homers and 100+ RBI in a season the 9 previous players to do it since the rookie of the year award began (1947) all won it

— Sarah Langs (@slangsonsports.bsky.social) 2026-08-29T19:07:32.184Z

That sent me scampering to the FanGraphs Rookie Leaderboards where you would see that Stewart, for all the fun counting stats, is the 7th best offensive rookie by fWAR (and is behind some (pitchers, as well), and the 9th best by wRC+.

But this article isn’t about Stewart, it is about the two fine young gentleman who top that wRC+ rookie leaderboard Esmerlyn Valdez and Munetaka Murakami. There are no many debuts more fun that those two. Murakami is going to have 30 HR any day now (I am writing Saturday, so maybe he already does?) and Valdez is on pace for 40, if only it were for those pesky months in Triple-A.

But Murakami and Valdez share something beyond prodigious power: a prodigious inability to make contact.

Among the 279 hitters with 250+ PA, Murakami’s 60.5% contact rate is the lowest in all of baseball. Valdez, at 64.7%, is the third lowest. More concerning is that they are lowest (Murakami at 71.5%) and second lowest (Valdez at 73.0%) in zone-contact rate. Yes, we know that pitchers who challenge them risk giving away a souvenir to someone far, far from home plate. But they also have a good chance to get a whiff.

This raises two questions:

1. How big of a problem is an abysmal z-contact rate?
2. How likely is a player to fix an issue like that?

The answer to the first question is that it is a big, but not insurmountable, problem. Over the five seasons from 2021-2025, there were 1,795 player-seasons of 200+ PA. Of those, 221 had a zone-contact rate under 80% and they averaged a 100.7 wRC+ (100.9 median). Pretty average. But as you get into lower contact rates, the numbers get worse. There were 113 seasons below 78% z-contact, and they had a 99.7 wRC+ (98.8 median). Below 77% you get 79 seasons with a 97.8 wRC+ (94.2 median). You can see what’s happening here.

Oddly, when you drop even lower, to below 76% or 75%, you get slightly better offensive results, but I think that is a combination of small sample noise and survivorship bias. If you are making contact at that low a rate, you better be getting results or you are getting removed from the lineup.

Sure enough, when we look at the names of players who posted good seasons with contact rates below 75%, you get a pretty uninspiring list (sorted from best wRC+ to worst):

Matt Wallner (x2), Nolan Jones, Rafael Devers, Mike Zunino, Zack Gelof, J.D. Davis (x2), Joey Gallo (x2), Patrick Wisdom 위즈덤, Javier Baez, Keston Hiura 히우라, Giancarlo Stanton, Luke Voit, Christopher Morel, Chas McCormick, Bobby Dalbec, Jose Siri, Chris Taylor, Brett Phillips, Jazz Chisholm Jr., and Bobby Bradley

Those names falls into three categories, more or less. You have Guys Who Flashed Fantasy Potential But Never Maintained It (Wallner, Jones, etc.). Guys Who Run Hot and Cold But Fantasy Managers Find Unreliable (Chisholm, Baez, etc.). And Guys We Hoped Would Be Good (Morel, Dalbec, etc.).

You also have Devers, who stands out as the one consistently good player in this group. But, it is worth noting that Devers one season on this list is 2025. He has regularly been at or near 80% z-contact in his career, and in only one distinctly unique season in which he had off-field issues with his team before being traded did z-contact become an issue.

When you raise the z-contact bar to 77%, you get 13 more seasons of 100+ wRC+, and this list is a bit different. Yes, it includes another appearance from Matt Wallner, as well as another from Devers. It also includes names like Luke Voit, Mickey Moniak, Heriberto Hernandez, Ryan Noda, and Triston Casas, who might feel right at home on the previous list.

But it also includes Aaron Judge, Nick Kurtz, and Giancarlo Stanton. For Judge, that one low z-contact season (76.7% in 2023) was very much an outlier for a guy with an 81.1% z-contact rate for his career.

For Stanton, decreasing z-contact has been an issue. From 2010-2018, the truly elite version of Stanton posted an 81.4% z-contact rate and a .381 wOBA. Over the last five years, including his limited time in 2026, that has dipped to 76.9% and his wOBA has falled to .331. Is that that the only reason Stanton is struggling? No. But it doesn’t help.

Kurtz is a challenging case because at just 923 career PA and with a .364 career BABIP, it’s a little hard to know what to make of his career stats. The results are great, but the high levels of swing and miss are very concerning. He also loses almost 9 percentage points off his HR/FB rate and more than 50 points off his wOBA away from Sacramento.

For our purposes, we can put him in the Judge/Stanton/Devers category of guys who can overcome low z-contact rates. But he may share one other trait with those guys: his sub-77% season (2025) might be an outlier. This year he has that rate up to 77.7%. Given the list of names we saw above, being in the “low but above 75%” category seems to matter.

So the answer to our first question seems to be that a low zone-contact rate makes it harder to succeed (as noted, the mean wRC+ for guys with a z-contact under 77% was 97.8 with a median of 94.2), but doesn’t make it impossible. But as you get extremely low – below 75% – it is exceedingly rare to maintain success over time. Putting up a positive offensive season with a sub-75% zone-contact rate is possible. Just ask Nolan Jones or Matt Wallner. Turning that into multiple years of sustained success is maybe no. Just ask Nolan Jones or Matt Wallner.

Which brings to our second question – how hard is it to fix that problem? After all, it looks like Kurtz did it (at least for now). And it seems Judge and Stanton dipped down and popped back up.

To answer that question, I started with the 1,795 player-seasons of 200+ PA between 2021 and 2025. I then I identified every player who had at least one season of a z-contact in the bottom decile (below 79.32%) from 2021-2024 (leaving out 2025 to make sure players had a chance to improve in the sample). And then I looked to see how many of them later had a season that was at the 25th percentile (82.62%) or better. Going a step further, I looked to see how many of those players maintained those gains, as defined by having a median z-contact of at least 82.37% (a 0.25% buffer around that 25th percentile number) moving forward.

This created a funnel that we can use to answer a few questions.

So, what does this funnel tell us?

1. Of the 105 players who had at least one bottom-decile z-contact season, only 2/3rd (67.6%) had another 200+ PA season in the future. For almost a third of players who have z-contact rates below 79.32%, that one season is all they got. Now, that might be injury related or it might be performance related, but it is a telling number.
2. Of the 71 who stuck around, only 23 (about 1/3rd of those, 32.4%) ever had a future season above the 25th percentile z-contact rate. Basically, once you demonstrate the “skill” of swinging and missing in the zone a lot, it is really hard to get back to even the bottom of the middle of the pack.
3. Of the 23 who did get back there, almost all of them (20, or 87.0%) maintained those gains.

I also pulled 2015-2019 data (intentionally leaving out the COVID-shortened 2020) and split that 105 playesr into two cohorts – one of players who had previously had a z-contact above the 25th percentile and one of players who had not. The idea was to separate the 2023 Judges from the 2025 Kurtzes. Is it easier to “get back” to good z-contact than to get there for the first time? The answer, it turns out, is no.

If the overall funnel was that 1/3 or players don’t get another 200+ PA season and 2/3rds of those that do never improve, the funnels for these two cohorts are pretty similar.

Players who had previously solid z-contact rates are a little more likely to improve, but it isn’t a huge number.

So if you are looking at the future for Murakami or Valdez and wondering if they are destined to be low-zone-contact hitters forever, the answer is no, but that doesn’t mean the data is cause for optimism.

Of the 105 players who posted bottom decile z-contact rate seasons from 2021-2025, nearly a third haven’t played another 200+ PA season and less than a quarter of the full population  them ever “fixed” their zone contact issues (21.9%). Having a 21.9% chance to fix the flaw isn’t 0%, but it isn’t particularly high. The good news is that if they do fix it, you can fairly safely assume they’ll keep their gains.

The one other note on this, though, is that Murakami and Valdez aren’t just putting up bottom decile seasons in z-contact. They are quite literally the two worst hitters in all of MLB at making contact in the zone. So what if we look at that same data but start with players who put up a z-contact season below the 5th percentile (77.29%)? That’s still a lot higher than Murakami and Valdez, and it limits us to just 61 total cases, but the results aren’t great.

Of those 61 players, 40 had a subsequetion 200+ PA season – effectively the same 2/3rds we saw in the other population. But only eight of those (20% of the 40 and 13.1% of the 61) ever got to a 25th percentile z-contact rate. The good news, again, is that all eight of those players maintained their gains. But getting there was a lot less common.

I am not telling you that you need to sell high on these two. I targeted a 25th percentile z-contact rate with my analysis, but there are players who under that 82.62% threshold who have been successful.

But it is the exception and almost no one survives much lower than that. Over the 2021-2025 stretch, 360 MLB hitters managed 1000+ PA – less than two full seasons worth of plate appearances. Of those, only 27 had a z-contact under 80%, only 13 were under 78% and only five were under 75%.

Valdez and Murakami are in some concerning company.