How to Evaluate Rookies & Prospects in Fantasy Baseball

In any format of fantasy baseball, prospects are fun. They are the new toy in the toy chest, and the unknown that they bring is half of the fun. But we often overrate them and the immediate impact that they bring. And just like that, we forget about them the following year.

Take, for instance, Luis Robert for 2020. Heading into the draft season, Robert has a ton of steam, and the projections like him a lot, too. But if he doesn’t perform up to those expectations, you’ll see him become a mid-teens round pick in 2021. In redraft leagues, it’s smart to approach with caution for the prospects — especially the top-performing players. They are typically drafted at a spot where the ROI is very, very little. Drafting is all about value, remember.

But what about long-term leagues? How should you approach rookies and prospects, and what should you look at to evaluate them? Let’s get you on the right track with a guide on how to approach them.

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Keep the list in mind
We love prospect lists. They are outstanding, and the people who put in the work on them typically do a fantastic job. But the thing to remember is that a lot of the top-100 prospect lists that you see online are geared toward real baseball value instead of fantasy value. I typically try to find the lists that gear toward fantasy baseball when evaluating prospects for fantasy purposes, though I still read the great work at places like FanGraphs, MLB Pipeline, and Baseball America.

Beyond our consensus fantasy baseball prospect rankings, sites like ProspectsLive, Fantrax, The Athletic, and Razzball are great sites to have bookmarked for your prospect evaluations that are geared toward the fantasy community. 

Knowing where the drop off happens
In 2011, Scott McKinney penned an excellent piece on the success and failure rates of top prospects. He looked at the top-100 prospects on Baseball America from 1990-2003, and he measured their success rate based on WAR. He found that 70 percent of the prospects failed, and that hitting prospects had a higher success rate than pitching prospects (more on that later).

Baseball America, in turn, did its own piece in 2019, looking at the success rate of top-100 prospects who became future all-stars. They found that 61 percent of all-stars from 2009-2018 were once top-100 prospects.

For me, I tend to look at the prospects in tiers. Top-10 prospects are near-locks to be above average to elite contributors. Eleven to 25 are above average. Twenty-six to 50 are average. From 51 on, it’s a coin flip, and there’s not much that separates 51 from, say, 150. It’s personal preference at that point.

So getting a top-100 prospect sounds great in a deal, but always push to get a top-50 guy or higher, when possible. 

Future production

Let’s take a look at MLB Pipeline’s top-10 prospects from each year, from 2010 to 2018. I’ll boldface those guys who haven’t been fantasy reliable fantasy options for a stretch of time and those who had a short stretch of being reliable options:

In all, there are few names in the top-10 from each class who haven’t been standout fantasy options for managers. Names like Brian Matusz, Dustin Ackley, and Desmond Jennings were misses, while others like Oscar Taveras, Jose Fernandez, and Tyler Skaggs all had their careers tragically cut short. 

In all, the success rate is pretty staggering. These are the types that you want to target.

What I look for
When I’m evaluating prospects, I’m looking to target those who are within my competitive window. If I’m looking like I can compete for a title for the next three years, I’m looking to grab players who are close in proximity to the big leagues. I’ll opt for guys like a Nico Hoerner over a Marco Luciano, who is years away. I’m OK with boring Josh Jung over an exciting Robert Puason, who could be great but will arrive when my window is closing. It’s why I have Andrew Vaughn over Jasson Dominguez in my 2020 First-Year Player Draft rankings. I expect Dominguez to be the superior fantasy option, but I want someone who is ready now.

While plate discipline is becoming less and less important as we move forward, I want to see someone at the plate who has their strikeout rate at a manageable percent. If they are striking out 25 percent in Double-A, I’m baking in growth to that as they advance to Triple-A and to the big leagues. The same goes with walk rate. If a player has a really low walk rate in the low-minors, it’s a red flag for me.

What about pitchers, you say?

Well, I typically fade them, especially in dynasty leagues. The success rate is so, so low with pitchers, and we see the arm injuries or flameouts all of the time with them. I’ll take the bat over the arm — prospect or big leaguer — nine times out of 10. 

But I’m a realist. I know you need arms to compete, so while I’ll always try to trade for major league arms with some top prospects, I will occasionally target advanced pitching prospects. I like college arms a lot in initial drafts, and that’s because they are closer to the big leagues and more advanced. That means I’ll miss out on the Mackenzie Gores of the world, but that’s OK. 

I’ll typically target guys who have a decent sample in Double-A and/or Triple-A, and I’ll typically fade the lower-level guys. There is just too much risk with them at an already risky position.

Lastly, be careful when reading the scouting reports on guys. There are a lot of prospect guys who are in love with each and every prospect, and those experts project them to be near-aces or middle-of-the-order bats. We need to pump the brakes and realize that those projections that are thrown out typically have a likely outcome of about 15 percent. 

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Michael Waterloo is a featured writer at FantasyPros. For more from Michael, check out his archive and follow him @MichaelWaterloo.