Prospect Variance and Blocking Catchers

The Winter Meetings always feature trades, but two stood above the fray last week. First, the Guardians traded Andrés Giménez to the Blue Jays in a two-part transaction that briefly left Cleveland with three lefty-hitting first basemen. Then the White Sox traded Garrett Crochet to the Red Sox for four prospects. The best of that group, Kyle Teel, happens to play catcher, the same position as Chicago’s top prospect Edgar Quero. They even have the same future value grade of 50, which is the cutoff for top 100 prospects.

The Guardians made an extra trade to avoid doubling up on similar archetypes, sending Spencer Horwitz to the Pirates for three young pitchers, but the White Sox just kept both catchers. I heard a lot of murmured questioning of that decision as I walked around the Dallas hotel that briefly hosted the center of the baseball universe. But I think both teams were acting rationally, and that worrying about Teel and Quero overlapping is silly. I can’t prove it for you – but I did come up with some data that will hopefully sway your opinion.

Cleveland’s case was straightforward. Steamer projects Horwitz as a 2.5 WAR/600 PA player. It projects Kyle Manzardo as a 1.8 WAR/600 PA player. Josh Naylor? Steamer has him down for 2.4 WAR/600 PA. Three players for two positions — first and DH. (Yes, Horwitz has played second base, too, but he really shouldn’t be a second baseman, and I don’t think the Guardians would’ve used him there.) One of them would ride the bench despite being an above-average contributor, a poor decision for a team that’s trying to maximize its resources. Something had to give.

On the other hand, there are the White Sox. They, too, traded a young star, and the best player they got back plays a position where they already had a similar option. Teel was our 42th-ranked prospect on our updated Top 100 list in 2024, a polished all-around catcher who we expect to reach the majors at some point in the next two years. Quero was our 40th-ranked prospect, and you’re never going to believe this, but he’s a polished all-around catcher who we expect to reach the majors at some point in the next two years.

What makes these two situations different? Time. Those three two-win first basemen? That’s what they are right now. All three can’t play in the majors at the same time, though, which means that one is blocking out the present-day value of the other. Given that the Guardians are focused on making the playoffs in 2025, that doesn’t really work. On the other hand, Teel and Quero aren’t valuable to the White Sox because of what they’ll do in 2025; for them, it’s more about the future.

When you hear “Top 100 Prospect,” don’t take that as a final proclamation on what a player will be. For example, our 2019 Top 100 list had a delightfully varied midsection:

Your future value is no guarantee of where you’ll end up. There are tons of uncertainty. You can think of a 50-FV prospect as more of a distribution of possible future outcomes:

You can quibble over what exactly this means. Are our estimates imperfect? Definitely. Do players improve or get worse in unpredictable ways? Absolutely. Is this randomness? Fate? Unforeseeable hard work and confidence? Something deterministic that we simply don’t have the tools to detect yet? I don’t have an answer for you. The point is that while the label we’re putting on both White Sox catchers now is the same, what they’ll actually turn into as major leaguers is far from certain.

That’s all fairly obvious, but the magnitude matters. If the spread of outcomes is narrow, if most prospects similar to Teel and Quero turn into broadly similar major leaguers, maybe worrying about them blocking each other is reasonable. If the spread is wide, or if the most likely outcome is failure, that’s less clear. Estimating that distribution of outcomes isn’t easy, but it’s certainly doable.

I made a few assumptions to get a rough idea of how this looks in real life. First, I assumed that the White Sox are trying to compete three years from now – I had to pick a number, and that one felt like a reasonable middle estimate. Next, I decided that I’d look at projected WAR per 600 plate appearances as an estimator. Finally, I had to pick a sample of real-life players to use as comparisons. I used all the position players with 50-FV grades on our Top 100 prospect list in a given year.

I wanted to avoid having the data overly corrupted by the lack of a 2020 minor league season, so I settled on using three years: prospects from 2019 projected for 2022, prospects from 2021 projected for 2024, and prospects from 2022 projected for this upcoming season. In plain English, I took our prospect lists and looked at how the players who were given a 50 FV developed over the subsequent three years. I used projections rather than results because not all of these players got full playing time, so small-sample variance would swamp the results otherwise. Similarly, I decided not to limit my sample to catchers with 50-FV ratings because there simply weren’t enough of them.

I chose to exclude pitchers from this study. I’d have to make assumptions about how many innings equate to 600 plate appearances, and they don’t seem obviously comparable to hitting prospects, so I’m keeping the two separate. That still gave me 158 observations, plenty enough for my purposes here.

My first observation: There’s a real chance of failure; 33 of the 158 hitters with a 50 FV were projected for 0.5 or fewer WAR per 600 plate appearances three years later. Some of those guys never made the majors. Some did and underperformed. Roughly 20% of the time, in other words, your solid hitting prospect never materializes into someone you can count on.

Another 20% of the prospects (34 out of 158) were projected for between 0.5 and 1.5 WAR per 600 plate appearances three years later. That’s a nice rotational player, more or less; 2.0 WAR per 600 PA is the league average. Speaking of that, another 40% (64 out of 158) projected for between 1.5 and 3.0 WAR three years down the road. That’s the biggest population, and also the central outcome. Plenty of solid prospects become solid players, nothing more or less.

The top end is more diffuse. There are 21 players between 3.0 and 4.0 WAR, five in the 4.0-5.0 range, and then Gunnar Henderson alone at the top, projected for nearly 6.5 WAR per 600 PA in 2025. Here are the data I used, in a very stripped-down version, if you feel like playing along at home.

Let’s try that chart again, this time with some odds on it:

Now that we have a distribution, we can think about what the White Sox are doing a little more clearly. Any individual 50-FV prospect has a 17% chance (in this data set, at least) of ending up as a player projected for more than 3.0 WAR three years down the road. But if you have two prospects playing the same position, there’s a one-in-three chance (31%) of developing an All-Star-caliber option, assuming their development is, broadly speaking, independent.

When you put it that way, what the White Sox are doing makes more sense. Having a 31% chance of developing a catcher who is a borderline All-Star or better sounds a lot better than a 17% chance. Even better, the risk of ruin decreases substantially when you have two catchers instead of one. Consider the Padres and Rays. They’re good teams, frequent playoff contenders with plenty of star-level performers. And yet, over the last three years, they’re 23rd and 24th in catcher WAR.

That unquestionably hurts their ability to compete in the playoffs – each are basically playing a roster spot short compared to their opponents. And what are they supposed to do about it? Good catchers are hard to acquire. You can’t just move someone over from a similar defensive position. The best ones mostly don’t make it to free agency. If you start with a bad situation, and can’t somehow convince the Braves and A’s to send you William Contreras for almost nothing (hi Milwaukee!), you’re out of luck.

With one top catching prospect, the data suggest that the White Sox would be looking at a bad outcome – a backup or complete washout – roughly 43% of the time. Imagine exiting a rebuild that took you half a decade and resulted in some absolutely miserable teams, only to have your new contender hamstrung by a lack of options at catcher. The odds of that happening dip to 18% if you instead have two 50-FV catchers to develop. So let’s look at our chart one last time, this time with the result of two 50-FV prospects at the same position:

No one wants to plan on failure. It would be great if every prospect panned out. But that just can’t happen – it’s not even mathematically possible. There are only so many wins to go around. Hoping your guys pan out isn’t a good team-building strategy; it’s important to have backup plans and redundancy. Volatile players at far-away timelines are risky, and I don’t see anything wrong with managing that risk by targeting an exciting prospect like Teel.

Maybe I’m preaching to the choir on this one. It feels pretty straightforward to me: Prospects fail, so there’s nothing wrong with having extras if you’re not trying to put them on your major league roster right this minute. But the concept of blocking is overused among prospects. Getting good players is a great idea. Where they play matters less than how good they are, and doubling up can be valuable if you’re trying to avoid leaving a hole in your roster. Variance is real – the good teams account for it in their decision-making.

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