Last time we talked about some ways to find breakout prospects before they move up lists by reading and listening to scouts, but there’s another place we can look for that – in the stats. FanGraphs.com Minor League Leaderboards offers us complete minor league stats from every level. There are many values we can filter on, so let’s look at which ones to use.
Using FanGraphs to View Minor League Stats
Level
We’ll start with “All Affiliated Leagues” but you can also use this if you want to find AAA guys who might get a call up, or low minors standouts under the radar.
Age
This should always be your first filter after selecting the level. You can leave it off if searching AAA, but if you’re looking for stashes, set it to under 25, which is about as old as a ranked prospect will be. If you’re looking at High A and below, drop it to 22.
wRC+ over 150
Weighted Runs Created + is a quick way to identify level-adjusted results but won’t tell you everything. You’ll want a few process stats to get that.
ISO over .200
This filters out the guys who are just racking up singles via high BABIPs. You’ll still see some of that with this filter, but it’ll weed out the speed-doubles and get you guys with at least average pop. We could limit BABIP to something like .400 but if a guy is raking. this will be high, and baseline is higher at lower levels than MLB.
What about Walks and Strikeouts?
I will sometimes look at K% and BB% when digging for hit tools but in a small sample size a guy who mashes won’t be overly concerned with plate discipline. Pitchers might also avoid the zone more with them. The proliferation of the robozone or ABS (Automatic Ball Strike) systems throughout the minors also create some wonky results. Hitters have a tendency to take more pitches when it’s new, trying to calibrate their own sense of what will and won’t get called.
I’ve also missed on a few high-profile prospects who I thought struck out too much, but do enough damage for it to work in Jackson Chourio, James Wood, and Bobby Witt Jr. – and taking the risk on Elly De La Cruz has paid off.
Example: Under 23s in AA
Applying these filters along with ISO and BABIP gets us down to 4 names.
If we click into a player, we’ll get their FanGraphs scouting grades. Let’s take the first name on the list, Joe Mack. We see that Mack was a comp pick for Miami in 2021, 31st overall. His standout tool is his power, listed at 35/50 game and 55/60 raw, reflecting a 20/30 grade hit tool – usually a red flag. But if we look at the results, we see that he hit .252 in 2024 while walking around 10% and striking out a hair under 25%, suggesting a better hit tool than the grade, approaching below average (45). His ISO (barely) topped .200 last year, popping 24 bombs at age-appropriate levels. He barely cleared the BABIP threshold at .395 so far this year, but I think the easiest conclusion here is that he’s a better hitter and is getting to his raw power in-game now. He carries the added risk of being a Catcher but is moving quickly and has a clear path to the Majors.
We also have a list of recent article mentions on his player page, where we find that he’s up to 65th on Eric Longenhagen’s most recent real baseball update, and with that power and proximity, fantasy lists are likely to follow suit soon. I also heard him mentioned on the Rotowire Prospects podcast recently. He’s currently available in all of my leagues, and I should probably fix that before I publish this.
Next up is Kemp Alderman a 2nd round pick in 2023, also for Miami. His carrying tool is also power, graded at present 80 raw, but with nothing else grading out above 30 current, and Hit being the only non-power grade getting to even 40 future. His walk and K rates also weren’t especially good or bad in 2024, but he only went yard 8 times across four levels – he was a little old for Low-A, so getting to High-A at 21 is about right. Unlike Mack, his 2025 BABIP is pretty reasonable at .327 with four homers already, and a surprising-for-his-speed, 7 stolen bases. I’m not sure these bags will translate, but as I’ve mentioned, Steals are as much about want as sprint speed. He’s also got the lowest strikeout rate of his pro career at 18.9%, and improvement there is one of my biggest green flags after seeing what Chourio and Wood have done.
There hasn’t been any mention of Alderman since the Fall league, when he hit a ball 119.5mph, supporting that 80 grade on his Raw. Checking other sources, we learn that a broken hamate bone limited his access to that power in the minors in 2024. No one added him based on those results, so seeing these numbers show he’s healthy to start and will likely change some opinions. If I have an open minors spot after all the recent promotions. I’m trying to fill it with Kemp Alderman.
I’ll leave the last two names for you to dig into. Play around with the settings. Under 20 at all levels is another good one, though you might lower the ISO threshold to .180. That’s fringy for established prospects but we don’t expect as much power from teens. Next week I’ll be looking at the newest tool for statline scouting, Prospect Savant (click for a sneak peek at Alderman’s AA statcast numbers from last year)
