MLB Equivalency and Aging Curves

On Monday, the Dynasty Guru debuted The Dynasty Guru’s Sortable MLB Equivalency Leaderboard, which projects 2019 MLB performance using Jordan Rosenblum’s MLB Equivalency Calculator and his research on typical MLB aging curves.  In his article, Jordan shares a list of the top 50 projected offensive players based on their performances last season and promised that we would begin using 2019 data shortly.  While the 2019 season is still in its infancy, in fulfillment of that promise, we have already begun looking at how this years’ performances have changed projected future peaks.  As the season progresses and players work through slumps and enjoy hot streaks, we expect that these early results will change drastically.  Please feel free to view the full projected wOBA leaderboards HERE.

The tables below were extracted from this new set of data to show how last years’ top projected offensive performers in the minor leagues have been impacted by early 2019 performances. This is a running list that we plan to update regularly that may provide you with some insight as to what direction these players are trending.  Of course, there are stipulations that everyone should be aware of when interpreting this information.

1. The season is very young and the sample sizes are small. The projections are less accurate at lower sample sizes. wOBA only becomes 50% reliable after ~400 plate appearances. I wouldn’t put much stock into early season performances for most players, though there are some interesting outliers worth monitoring.
2. This first list includes rookies (<130 MLB at bats) of some high-profile players with MLB experience, such as Eloy Jimenez and Fernando Tatis Jr., as well as players that dominated lower levels of the minor leagues (perhaps unsustainably), such as Malcom Nunez, who set the Dominican League ablaze last year.
3. It’s worth noting that our offensive “projections” simply capture translated wOBA and general aging growth. wOBA (weighted on-base average) is a metric that aims to measure a player’s overall offensive contributions per plate appearance.  If you are not familiar with this metric, please use the scale below and feel free to read up on it on Wikipedia to familiarize yourself with how it works (https://en.wikipedia.org/wiki/WOBA).

wOBA Scale

2018’s Top Prospects by Projected Peak wOBA

Table 1: 2018 Top Players with MiLB At-Bats in 2018 by Projected Peak wOBA

Interpreting the Updated Figures

Out of last year’s top minor league performers, the early season results have not drastically altered many peak wOBA projections.  Kyle Tucker has clearly off to slower starts, but it is expected that more at bats will help bring his projections closer to being in line with where he finished in 2019.

Of minor leaguers still on this list, nobody has improved his peak projection more than Yordan Alvarez, whose red-hot start has pushed his future wOBA projections to practically unheard-of levels, an increase of 33% over his projections from 2019.  He’ll certainly regress some throughout the year, but this bodes well for his trajectory.

While Alvarez has had an incredible start to the season, he is not the top peak performer of 2019 – that honor belongs to none other than Luis Robert.  The table below represents the top 50 players by projected future wOBA based on 2019 performance. You’ll find many of these names generating a lot of buzz in the prospect community given their hot starts.

2019’s Best Performers by Projected Peak wOBA

Table 2: 2019 Top Players with MiLB At-Bats by Projected Peak wOBA

Interpreting the Early Performances

This table contains some well-known prospects such as Robert, Alvarez, Carter Kieboom, and Gavin Lux, as well as some potential high-rising sleepers that could help your team out soon if they can prove their early pace to be sustainable, such as Ty France and Roberto Ramos (the former who was just called up to San Diego!).  Players on this list with a lower percentage change are perhaps the most interesting, as their starts validate last year’s performance.  These players include Nolan Gorman, Alejandro Kirk, and Jarred Kelenic.

We will continue to update these leaderboards throughout the year to try and help you identify impactful talent for your fantasy squad!