The Next Generation of MLB Stars

2024 | Minor League Baseball Photos | Minda Haas Kuhlmann

Evaluating MLB prospects is an especially uncertain process. Unlike other sports, when MLB players get drafted, they are still likely three to four years away from playing at the major league level, which means scouts are often tasked with projecting what an 18-year-old will look like as a 22-year-old.

While data-driven scouting has become more sophisticated, no modeling technique compares to RBP in capturing the way scouts apply their unique knowledge. Scouts will often assign a range of outcomes for a prospect, using past prospects as a point of comparison. RBP does the same thing. Based on a powerful statistical measure of past prospects’ similarity to the current prospect and their informativeness, RBP identifies the players and predictive variables that have the most useful patterns for forming each individual prediction.

RBP understands that even the highest ranked prospects are far from certain and uses a reliability-weighted average of predictions from many combinations of players and predictive variables to guard against overrating or underrating a prospect.

Past Prospect Evaluation

To demonstrate RBP’s value in prospect evaluation, we analyzed the 2018 minor league pitching class. Using the 2019-2024 seasons as our sample, these players have now reached a stage where their career performance can be meaningfully assessed against their prospect rankings.

Below is a table comparing RBP’s predictions to FanGraphs’ prospect rankings for the same group. This is intended purely as a point of comparison — FanGraphs does excellent work in prospect evaluation.

RBP was able to identify numerous undervalued pitchers inside of its top 100 that were outside the consensus 100 prospects. This undervalued group included current ace-caliber pitchers Framber Valdez, Zac Gallen, Michael King, and Ranger Suarez.

These prospect rankings also highlight the value of fit, which measures the reliability of a prediction. (See the Deep Dive section of this newsletter for a detailed description of fit.) Intuitively, players at the higher Minor League levels have much more reliable predictions than players at the lower levels, as confirmed by fit.

Current Prospect Predictions

Relevance-Based Prediction’s current number one Minor League pitcher is Bubba Chandler. Some players that relevance identified as having similar Minor League profiles to Chandler are Michael Kopech, Noah Syndergaard, Alex Reyes, and Hunter Greene.

One pitcher RBP assesses as underrated is Jack Leiter, as he is in RBP’s top 20 pitchers but outside the consensus top 100. After starting out as a highly touted prospect, Leiter struggled with control issues throughout the Minor Leagues and during his 2024 Major League debut. RBP identified several players who have had control issues but have become successful as Major Leaguers as key to forming Leiter’s prediction, including Grayson Rodriguez, Reese Olson, and Julio Urias.