Minors to the Majors: MiLB Batted Ball Baselines & Leaders
Note: Do to a calculation error involving popups, the values initially report were off by a small bit. Everything is corrected now.
Our Dark Overlord continues to install enhancements to FanGraphs. One item which he has sneaked in over the weekend in Swinging Strike (must add to custom dashboard) and Groundball Rates for minor league pitchers (example). With the data now available to query, it’s time to find the league specific baselines and compare some highly touted prospects. Today, I will just concentrate just on the batted ball data.
Anytime new data becomes available, the baselines values are the starting point for an analysis so comparisons can be made. First, here are the overall league ground ball rates from 2016.
| Level | GB% | LD% | FB% | PU% |
|---|---|---|---|---|
| MLB | 44.7% | 20.7% | 34.6% | 3.4% |
| AAA | 44.9% | 20.6% | 34.6% | 7.3% |
| AA | 45.4% | 20.1% | 34.5% | 7.3% |
| A+ | 45.5% | 19.8% | 34.7% | 7.5% |
| A | 46.0% | 19.3% | 34.7% | 7.5% |
| A- | 47.9% | 18.8% | 33.3% | 7.8% |
| Rookie | 47.9% | 20.8% | 31.3% | 8.6% |
There is some funkiness going on in Rookie Ball and the Majors but the general trend is for ground ball rates to drop as the level approached the majors. Generally, the numbers are steady. With the league averages out of the way, I will move onto pitchers.
Pitchers
For pitchers, I will use a starting pitcher baseline. Combining starters and relievers causes a mess. Additionally, the pitchers who fantasy owners care about in the minors are normally the starters.
For pitchers, I consistently use ground-ball rate to describe a pitcher’s batted ball profile. It allows owners to understand the good and bad values for just one metric. To get the average starter values, I compared players from 2014 to 2016 in which they started at least half their games and pitched a minimum of 40 innings. I found the median value and set it to a 50 (Average) value. Then I found the standard deviation and added it to the median value, and graded it 60. I continued the standard deviation addition to an 80 grade. Finally, I subtracted the standard deviation value from the median to create the below average grades. Here are the results.
| Grade | Description | AAA | AA | A+ | A | A- | Rookie |
|---|---|---|---|---|---|---|---|
| 80 | Outstanding | 65.0% | 66.5% | 66.8% | 66.6% | 68.6% | 69.1% |
| 70 | Very Good | 58.0% | 59.2% | 59.6% | 59.6% | 61.5% | 62.1% |
| 60 | Above Average | 51.0% | 51.9% | 52.4% | 52.6% | 54.5% | 55.0% |
| 50 | Average | 44.0% | 44.5% | 45.3% | 45.6% | 47.4% | 48.0% |
| 40 | Below Average | 37.0% | 37.2% | 38.1% | 38.6% | 40.3% | 40.9% |
| 30 | Well Below Average | 29.9% | 29.9% | 30.9% | 31.6% | 33.2% | 33.8% |
| 20 | Poor | 22.9% | 22.5% | 23.7% | 24.6% | 26.1% | 26.8% |
Remember, this grade just informs us on how the pitcher performs compared to the rest of the league on groundballs. Being an extreme flyball pitcher also has an advantage. From some of my historical work, pitchers start seeing an ERA below their ERA estimators with a 70 grade or higher or a grade under 30.
Besides the groundball numbers, I decided to run the Popup% (FB%*IFFB%) for a reference.
| Grade | Description | AAA | AA | A+ | A | A- | Rookie |
|---|---|---|---|---|---|---|---|
| 80 | Outstanding | 15.4% | 15.8% | 15.1% | 15.3% | 16.7% | 18.5% |
| 70 | Very Good | 12.6% | 12.9% | 12.4% | 12.7% | 13.6% | 15.1% |
| 60 | Above Average | 9.8% | 10.1% | 9.7% | 10.0% | 10.6% | 11.6% |
| 50 | Average | 7.0% | 7.2% | 7.1% | 7.3% | 7.5% | 8.2% |
| 40 | Below Average | 4.1% | 4.3% | 4.4% | 4.6% | 4.4% | 4.8% |
| 30 | Well Below Average | 1.3% | 1.5% | 1.7% | 2.0% | 1.4% | 1.3% |
| 20 | Poor | -1.5% | -1.4% | -1.0% | -0.7% | -1.7% | -2.1% |
A high popup rate may be a sign of a why a pitcher may be over-performing at a certain level.
With the overall values known, here are the pitchers on Baseball America’s top 100 prospect list. I found their combined 2016 and 2017 groundball and popup rates since the 2017 season is just starting.
| Name | GB% | Popup% |
|---|---|---|
| James Kaprielian | 66.7% | 8.3% |
| Riley Pint | 57.3% | 6.5% |
| Sixto Sanchez | 56.4% | 6.1% |
| Ian Anderson | 55.2% | 6.9% |
| Jason Groome | 54.6% | 4.6% |
| Yadier Alvarez | 53.1% | 4.8% |
| Dylan Cease | 52.0% | 2.9% |
| Lucas Giolito | 51.5% | 3.9% |
| Mike Soroka | 51.3% | 6.3% |
| Cody Reed | 50.7% | 5.8% |
| Erick Fedde | 49.6% | 6.0% |
| Brandon Woodruff | 49.5% | 8.1% |
| Sean Reid-Foley | 49.2% | 6.8% |
| Tyler Beede | 48.1% | 7.1% |
| Amir Garrett | 47.6% | 8.8% |
| German Marquez | 47.2% | 7.2% |
| Mitch Keller | 46.7% | 7.2% |
| Anderson Espinoza | 46.5% | 8.2% |
| A.J. Puk | 46.2% | 8.8% |
| Anthony Banda | 45.9% | 6.8% |
| Justus Sheffield | 44.9% | 8.3% |
| Justin Dunn | 44.8% | 4.8% |
| Cal Quantrill | 44.6% | 4.1% |
| David Paulino | 44.1% | 9.5% |
| Francis Martes | 43.5% | 7.1% |
| Jeff Hoffman | 43.2% | 4.2% |
| Luis Ortiz | 43.2% | 8.1% |
| Stephen Gonsalves | 42.4% | 12.8% |
| Sean Newcomb | 42.3% | 8.1% |
| Tyler Glasnow | 41.8% | 12.1% |
| Michael Kopech | 41.1% | 15.2% |
| Kolby Allard | 41.0% | 7.5% |
| Jharel Cotton | 40.8% | 10.2% |
| Alex Reyes | 39.2% | 12.4% |
| Triston Mckenzie | 38.6% | 12.5% |
| Josh Hader | 38.2% | 9.9% |
| Luke Weaver | 38.0% | 11.3% |
| Franklin Perez | 36.9% | 10.6% |
| Reynaldo Lopez | 35.8% | 9.0% |
| Matt Manning | 34.9% | 11.6% |
| Jose De Leon | 34.5% | 10.8% |
| Brent Honeywell | 31.0% | 13.3% |
On average, these pitchers have an above average groundball rate. The one pitcher who stood out to me was Riley Pint. He’s known for 100 mph fastball but not his groundball rates. If it stays near 60%, he could be elite, even in Colorado.
With the pitchers done, time to move onto the hitters.
Hitters
I followed the same procedure for hitters as I did with pitchers by putting the hitter’s ground ball tendencies on a 20-80 scale (min 40 PA, 2014-2016). Normally, hitter groundball rates aren’t used but I find them extremely helpful to determine a hitter’s swing path. A high ground ball rate means a slugger will probably need to rework his swing for line drives as he gets closer to the majors.
| Grade | Description | AAA | AA | A+ | A | A- | Rookie |
|---|---|---|---|---|---|---|---|
| 80 | Outstanding | 68.4% | 68.4% | 70.5% | 71.6% | 75.8% | 74.5% |
| 70 | Very Good | 60.4% | 60.6% | 62.3% | 63.1% | 66.6% | 65.5% |
| 60 | Above Average | 52.3% | 52.7% | 54.1% | 54.7% | 57.4% | 56.4% |
| 50 | Average | 44.3% | 44.9% | 46.0% | 46.3% | 48.2% | 47.4% |
| 40 | Below Average | 36.2% | 37.0% | 37.8% | 37.9% | 39.0% | 38.3% |
| 30 | Well Below Average | 28.2% | 29.2% | 29.6% | 29.4% | 29.8% | 29.3% |
| 20 | Poor | 20.1% | 21.4% | 21.4% | 21.0% | 20.6% | 20.2% |
The one item to notice with hitters, the deviation from average is a bit more than that of pitchers.
Besides the groundball rate, I have also created the same information for line drives for reference.
| Grade | Description | AAA | AA | A+ | A | A- | Rookie |
|---|---|---|---|---|---|---|---|
| 80 | Outstanding | 34.2% | 33.3% | 31.6% | 31.8% | 33.0% | 34.2% |
| 70 | Very Good | 29.6% | 28.5% | 26.8% | 27.2% | 28.0% | 28.2% |
| 60 | Above Average | 25.0% | 23.8% | 21.9% | 22.6% | 23.1% | 22.2% |
| 50 | Average | 20.4% | 19.1% | 17.1% | 18.0% | 18.1% | 16.2% |
| 40 | Below Average | 15.8% | 14.4% | 12.2% | 13.4% | 13.1% | 10.2% |
| 30 | Well Below Average | 11.2% | 9.7% | 7.4% | 8.8% | 8.2% | 4.2% |
| 20 | Poor | 6.6% | 5.0% | 2.5% | 4.2% | 3.2% | -1.8% |
It’s not a surprise to see line drive rates increase as hitters gain strength and get closer to the majors.
Now that the averages are known, here are how hitters in Baseball America’ top 100 rank according to their groundball rate.
| Name | GB% | LD% |
|---|---|---|
| Blake Rutherford | 59.3% | 17.7% |
| Ronald Acuna | 54.6% | 19.2% |
| Mickey Moniak | 54.6% | 17.9% |
| Raimel Tapia | 53.8% | 17.7% |
| Kevin Newman | 53.5% | 19.5% |
| Nick Gordon | 51.5% | 20.9% |
| Amed Rosario | 50.1% | 21.5% |
| Leody Taveras | 49.7% | 17.7% |
| Kyle Lewis | 49.5% | 14.3% |
| Jorge Alfaro | 48.6% | 22.0% |
| Delvin Perez | 48.1% | 17.6% |
| Ozzie Albies | 46.9% | 20.6% |
| Chance Sisco | 46.2% | 27.6% |
| Victor Robles | 45.9% | 17.7% |
| Manuel Margot | 45.9% | 24.2% |
| Gleyber Torres | 45.9% | 22.6% |
| Josh Bell | 45.8% | 22.6% |
| Rafael Devers | 45.7% | 23.3% |
| Alex Verdugo | 45.5% | 22.4% |
| Anthony Alford | 45.3% | 24.5% |
| Corey Ray | 45.0% | 23.0% |
| Bradley Zimmer | 45.0% | 23.3% |
| Albert Almora Jr. | 44.3% | 27.1% |
| Lewis Brinson | 44.2% | 16.3% |
| Franklin Barreto | 43.6% | 22.1% |
| Yoan Moncada | 43.2% | 27.3% |
| Carson Kelly | 43.0% | 25.5% |
| Clint Frazier | 42.9% | 23.0% |
| Brendan Rodgers | 42.8% | 23.3% |
| Francisco Mejia | 42.7% | 23.7% |
| Eloy Jimenez | 42.5% | 21.5% |
| Ian Happ | 42.5% | 21.5% |
| Dominic Smith | 42.4% | 23.8% |
| J.P. Crawford | 41.4% | 19.9% |
| Dansby Swanson | 41.1% | 23.2% |
| Kyle Tucker | 41.0% | 25.6% |
| Willy Adames | 40.7% | 25.0% |
| Willie Calhoun | 40.7% | 20.1% |
| Rowdy Tellez | 40.5% | 20.5% |
| Jake Bauers | 39.9% | 22.3% |
| Casey Gillaspie | 39.8% | 25.0% |
| Jorge Mateo | 39.0% | 16.8% |
| Nick Senzel | 39.0% | 21.2% |
| Vladimir Guerrero Jr. | 38.9% | 20.1% |
| Austin Meadows | 38.8% | 20.5% |
| Hunter Renfroe | 36.9% | 19.3% |
| Zack Collins | 36.6% | 15.2% |
| Isan Diaz | 36.0% | 18.8% |
| Tyler O’Neill | 35.9% | 18.2% |
| AJ Reed | 33.0% | 25.2% |
| Andrew Benintendi | 32.7% | 22.7% |
| Aaron Judge | 32.1% | 25.0% |
| Cody Bellinger | 30.4% | 21.4% |
| Matt Chapman | 29.8% | 21.4% |
Two names stick out to me, Mickey Moniak and Raimel Tapia. Both have GB% grades near 65. Not good.
The one issue I have with Moniak is that his bat control is too good and he’s developed some bad habits. He is used to swinging at and hitting everything (see Javier Baez). As the pitchers get better, he’s going to have more and more plate discipline issues. Additionally, he may still make contact out of the strike zone and just generate weak contact. He needs to show that he can adjust and grow as a hitter.
Tapia seems like a poor man’s DJ LeMahieu but without the walks and power and a little more speed. Tapia will be a high contact Colorado hitter and these individuals post decent batting averages. Tapia problem is one I have been bringing up recently with hitting prospects, the focus on batting average when discussing a the hit tool. Tapia has a 60-grade hit tool (FanGraphs, Baseball America, and MLB.com) but doesn’t have a good approach at the plate. He has swung at pitches out-of-the-zone 47% of the time in the majors (30% is league average). Plate discipline needs to be a component to the Hit tool.
That’s it for today. Lots of new data to help answer some age-old questions. I’ve gone over some of the minor league batted ball baselines and will continue the research.Until then, happy prospecting.
Jeff, one of the authors of the fantasy baseball guide,The Process, writes for RotoGraphs, The Hardball Times, Rotowire, Baseball America, and BaseballHQ. He has been nominated for two SABR Analytics Research Award for Contemporary Analysis and won it in 2013 in tandem with Bill Petti. He has won four FSWA Awards including on for his Mining the News series. He's won Tout Wars three times, LABR twice, and got his first NFBC Main Event win in 2021. Follow him on Twitter @jeffwzimmerman.
Overall, I love this – well done, Jeff!
One minor note: “Plate discipline needs to be a component to the Hit tool.”
I’d prefer to see a separate Plate Discipline tool as opposed to lumping it in to the Hit tool. Just a personal preference, but this could be very helpful for identifying players who eventually end up following the 3 True Outcomes path – one can have a mediocre hit tool but if they have plus raw power and plus plate discipline, they can be an average or better hitter.