What’s Become of Prospects Kind of Like Yoan Moncada?

Part 1 is over. Part 1 was figuring out which team was going to sign Yoan Moncada, and now we know, with the Red Sox having given up more than $60 million for the right to try to make him into something. Most conspicuously, the Sox beat out the Yankees; less conspicuously, the Sox beat out everyone else. Moncada joins an organization with a silly amount of talent and resources, and he is now presumably Boston’s No. 1 prospect. Not a whole lot of prospects better than Blake Swihart, either. So that’s meaningful.

Now we move on to Part 2. What’s Part 2? Figuring out what Yoan Moncada is going to be. You can kind of deduce what teams expect him to be — based on the price, and based on all the attention, Moncada figures to be some kind of big-leaguer, with a high ceiling. But what have we seen from prospects like this before? Moncada’s going into his age-20 season. We can put some numbers to this, trying in a way to project the unfamiliar. Let’s scan some historical top-prospect lists.

Here’s as good a place to start as any — Moncada’s potential timeline. This is total guesswork, of course, but I think it’s pretty reasonable. Moncada’s young! He’ll spend 2015 in the minors. And based on his age, it wouldn’t be a surprise if he spent 2016 in the minors, too. Maybe he’d get a September cup of coffee. Then the next year, if Moncada were ready or just about ready, you’d expect the Red Sox to play with his service time such that he didn’t pick up a full year. That would set him up for six more years of team control, through 2023 and age 28. Maybe baseball will change these rules when they negotiate the next CBA, but I’m not going to factor that in until I have a good reason to. Moncada’s 19 right now — this has him under control through 28.

Great! Now then. What’s Moncada as a prospect at the moment? One thing we know for sure is that he’s a position player, and not a pitcher. And he’s young — younger than many quality prospects. Kiley said he’d put Moncada somewhere around No. 5 – 12 on a top-100 list. Baseball America said they’d put Moncada around No. 10. Here’s a little more explanation on that. It’s safe to say, I think, Moncada is a top-20 sort, with the major thing holding him back being that he’s totally unproven in the States. The air of mystery is part of what makes him appealing, but it’s also a huge part of the risk. Young players are risky. Young players who have never played here before are risky.

I wanted to generate some numbers based on peers. So I looked at all the Baseball America top-100 lists from 1990 – 2008. From each list, I selected just the top 20, and then I selected just the position players. Finally, I selected just the position players going into their age-20 seasons, or younger. This introduced a little extra upside, and a little extra risk. The last step was figuring out what the players did through their age-28 seasons, to try to match the projected Moncada timeline above. Granted, some players reached the majors sooner, so they got more time to accumulate WAR, but the Red Sox wouldn’t complain if Moncada were a super-fast mover. This should provide some idea of how often these guys have turned into good players, and how often these guys have busted.

For the few players included who haven’t yet reached their age-28 seasons, I added in projections. Seemed safe. And while I know relying on Baseball America introduces certain biases, no other source goes back so far, and remember, we’re looking at top-20 prospects, so everyone would’ve loved these guys. These are the best young position-player prospects over nearly 20 years. The graph:

You notice the sample size — after I got rid of duplicate entries, I was left with 47 players. That’s 47 position-player prospects who ranked in the top 20 somewhere while entering their age-20 seasons, or younger. This is our group of approximate Yoan Moncada “peers”. No other steps have been taken to narrow down to certain skillsets. It’s a group that includes both Ivan Rodriguez and B.J. Upton (or Melvin Upton Jr., now, I suppose). Make of this whatever you want.

Immediately, you might notice that 16 players didn’t even rack up 5 WAR by 28. Casey Kotchman didn’t do it. Andy Marte didn’t do it. And another six players generated somewhere between 5 – 10 WAR by 28, including Sean Burroughs and Corey Patterson. “Bust rate” is subjective, and I don’t know how much the Red Sox are expecting, here, but we’re at 25 out of 47 players who generated at least 10 WAR by 28. That’s 53%, or only a little better than half. You understand the risk of this. The younger a player is, and the further he is from the majors, the more opportunities there are for his career to be derailed.

You can’t just focus on the downside, though, because if anything that’s the opposite of what people do with young prospects. Pretty obviously, Alex Rodriguez is the hero of the list. He was ranked No. 6 before 1994, so, before his age-18 season. At that point, he’d never played professionally. Miguel Cabrera was ranked No. 12 before 2003, so, before his age-20 season. At that point, he hadn’t played above advanced Single-A. Andrew McCutchen was ranked No. 13 before his age-20 season, and he had just a month of experience in Double-A. The Red Sox would probably like it if Moncada followed the McCutchen timeline.

The average of the group, through 28, is 16 WAR. A standard deviation? 17 WAR. So, yeah, turns out these players are volatile. The median is a hair below 12 WAR, with the median playing time being about 3,600 plate appearances. All but six of the players cleared 1,000 times at bat by 28, so opportunities were mostly there. Every single player reached the majors. Joel Guzman hung out in the majors the least, and I just learned he was also terrible one year in Japan. Been a rough career for Joel Guzman.

The point is what you knew: there’s a big range of potential outcomes for Yoan Moncada. There’s a real chance he develops into a superstar. There’s a real chance he develops into Andy Marte, which is to say, there’s a real chance he develops no more than he already has. You already understand that these young guys can be boom-or-bust types, but this should at least provide you with some rough probabilities. Good deal for the Red Sox? No point in my trying to guess. What I can say for sure: the Red Sox can afford it. So in that sense, sure, deal’s good enough. Yankees could’ve afforded it, too. I guess someone has to be the winner and someone has to not be the winner.