Baseball: How minor league statistics differ

The dog days of summer bring fewer off days and more fatigued pitchers.

Teams are being extremely responsible with their prized arms, with the Angels and Padres among those going with six-man rotations. Other teams will adopt this philosophy as we move through the summer months.

We’re also going to see more teams try to steal rest by calling up spot starters from the minor leagues. And we’ll start to see more position players get called up as well, either because of injury on the major league roster or a promotion based on their own merits.

It’s important to apply context to the minor leaguers and their statistics because leagues in Double-A and Triple-A are very different, not only from MLB but from each other.

Let’s take a look at the differences between the minors and MLB first, then take a look at the differences between the different minor leagues.

Minors vs. Majors

The minor leagues have become a test lab for potential MLB changes. Some rule changes likely to be implemented at the MLB level are already being used in the minors. Minor leaguers are accustomed to playing under these rules, so playing in the majors becomes a completely different experience.

Pitch clock: The pitch clock is one huge difference. Pitchers in the minors get 14 seconds between pitches with nobody on base and 18 seconds with a runner on base (19 seconds in Triple-A). There is a 30-second clock between batters. Batters get one “timeout” per plate appearance. If a pitcher is not ready, an automatic ball is assessed, while a hitter gets an automatic strike for being tardy.

Of course, there is no clock in the majors. MLB hitters may not like how fast minor league pitchers work. Minor league pitchers may be thrown off by how much longer everything takes. There is really no way of knowing who will be affected, but it’s an important distinction between the minors and majors.

Robot umps: Triple-A (and Low-A Southeast) are using robot umps, but mainly in the Triple-A West Division, which is the Pacific Coast League. The league adopted robot umps on May 17. The Charlotte Knights of the Triple-A International League have used robot umps all season, but that is the only ballpark using them in the East Division.

The strike zone is 19 inches wide, so it includes one inch on either side of the plate. The height of the zone is based on player height. That is much different than the variable strike zone pitchers get with umpires in MLB.

The shift: Defensive positioning is a hot-button issue for baseball, and it seems likely MLB will change the rules regarding the shift for 2023. All three Double-A leagues have banned the shift. Two infielders must be to the left and right of second base when the pitcher delivers the pitch. A violation results in an automatic ball. High-A and Low-A have also banned the shift this season.

Larger bases: All levels of the minor leagues are using bigger bases. Home plate remains the same size, but the three bases around the diamond are 18 inches on each side instead of 15.

What does all of this mean? The larger bases and the pitch clock have increased stolen-base attempts and success rates at the minor league levels using both of those alterations. The shift policies are obviously quite different and can dictate the way a pitcher attacks a hitter. Theoretically, more offense would come as a result, especially because fielding in the minor leagues is generally worse than what we see in the majors.

Minors vs. Minors

The rule differences matter, but the most important differences between the leagues are related to weather, atmosphere and environment. Pitcher and hitter stats vary greatly because some teams are in much better hitting environments than others. That means we need to consider player stats in the proper context.

Triple-A

International League: Mostly made up of teams located east of the Mississippi River, the IL has a lot less offense than the Pacific Coast League. There are only three teams west of the Mississippi (St. Paul, Iowa, Omaha) and quite a few teams in the Northeast or on the Eastern seaboard. There are no teams at elevation and many play in what we would consider to be cooler-weather cities.

Pacific Coast League: The PCL is made up of teams out West and down South, including cities such as El Paso, Albuquerque, Reno and Salt Lake City. As we know, the ball travels farther in thinner air. There are also some teams in very hot cities such as Las Vegas and in Texas.

What does this mean? Going into Monday’s off day (another difference: all minor league teams are off on Mondays), teams scored an average 4.97 runs per game in the International League but 5.82 runs per game in the Pacific Coast League. There are only 10 teams in the PCL, so hitters have more familiarity with the pitchers they face, but the offensive increase is largely a byproduct of better hitting conditions.

Pitchers in the IL have a 4.61 ERA compared to 5.42 ERA in the PCL. HR/9 is 1.1 in the IL and 1.3 in the PCL. The Sugar Land Space Cowboys are the lowest-scoring team in the PCL with 5.12 runs per game. Eleven IL teams average fewer runs than that.

If you are analyzing pitcher or hitter stats in the PCL, they have to be graded on a different level than the IL.

Double-A

Similarly, a lot of different geographic locations can skew player performance in the three leagues in Double-A. Pitcher and hitter stats are going to vary greatly because of the impact of temperature and humidity on the flight of the baseball.

Eastern League: The EL is made up of 12 teams around the Great Lakes or in the Northeast. Those are cooler-weather cities for a good portion of the season and likelier to have conditions that suppress offense.

Southern League: The SL has eight teams, so hitters are seeing the same pitchers quite often. All of these teams are in warmer-weather locations with more humid conditions, both of which help the baseball travel.

Texas League: The TL has 10 teams and, as we know, it gets quite hot in Texas. The Texas League actually includes two teams in Arkansas, two in Oklahoma and one in Missouri.

What does this mean? EL teams have scored an average of 4.54 runs per game, while SL teams have scored 5.1 and TL teams have scored 5.61. Once again, you have to apply the proper context to player performance. It is far easier to hit for power in the Texas League than in the Eastern League. It is easier to put up good numbers as a pitcher in the Eastern League than in the other two leagues.

Pitchers collectively have a 4.30 ERA in the EL, but a 4.66 ERA in the SL and a 5.19 ERA in the TL.

As teams are promoting their youngsters and starting to make trades, more and more of these minor league players will get a chance to show what they can do at the MLB level. It will help you tremendously to know more about these call-ups than the sportsbooks so you can try for a more accurate handicap of each game.