Making Sense of the Arizona Fall League Hitting Enviroment
Chris Clegg breaks down why you should not put much stock into AFL stats.
The Arizona Fall League has long been known as one of the more hitter-friendly environments in baseball. Given this, how much do the numbers matter? Having more Statcast available this year helps, as four of the six stadiums have scrapable data for hitter data, but given what I am about to say, how much stock can we put in that?
Comparing the data peer to peer can be helpful because all hitters in the Arizona Fall League are in the same environment. So a performance from a hitter like Josue Briceño, who just turned 20 at the end of September, matters. He was the best hitter in the league in nearly every aspect and did it as one of the youngest. Factoring in his age and the fact he was better than every hitter in the league is notable.
Arizona Fall League Stats
But what about the numbers and league averages? Well, after the dust settled and all six teams played 30 games, the league-wide slash line sat at .270/.373/.434, and teams averaged 6.3 runs per game. For reference, in 2023, AFL teams averaged 5.67 runs per game, and the league-wide slash sat at .253/.354/.413.
The league-wide runs per-game total was the highest we have seen since 2008, and the first time the league-wide OPS was over .800 since 2011. Was it better hitters? Was the quality of the pitcher worse this year than in previous years? There were likely several factors.
When looking at Minor League regular season data, the most comparable hitting environment is probably the California League(Single-A) or the Pacific Coast League (Triple-A). In the PCL in 2024, teams averaged 5.69 runs/game, and the league-wide slash line sat at .268/.356/.442. In the Cal League, 5.51 runs per game, with a .250/.353/.379 slash.
When looking at the AFL, we can attribute the higher OBP to pitching. The walk rate of 13 percent is not far off from what we see in the Dominican Summer League. Hitters with any bit of plate discipline will walk at a high clip.
How Is Power Affected in the Arizona Fall League?
But what about from a power standpoint? I think about this Matt McLain swing a lot. It left the bat with an exit velocity of 102 mph and a 32-degree launch angle. It traveled 431 feet. It seemed a bit crazy to see the ball travel that far with those batted ball metrics, so I went and looked at historical data.
Batted balls with similar exit velocities and launch angles produced an average hit distance of 392 feet in MLB. Only five batted balls in 2024 with similar metrics traveled at least 430 feet, and all were in Coors Field.
We know that in an environment like the desert, the ball will fly, but here is where things get interesting. The average exit velocity for AFL hitters was north of 90 mph, and the hard-hit rate was just shy of 45 percent. In the PCL, those numbers were 87.5 mph and 35.5 percent. The quality and age of hitters are also quite different in Triple-A. In the International League(East Coast AAA), the league-wide numbers were 87.8 mph and 35.6 percent.
Now, let’s dial it back to Single-A, where the average exit velocity in 2024 sat at 86.7 mph, and the hard-hit rate was 32.2 percent. The Arizona Fall League numbers are wild to see. We expect the ball to travel further; that is a given. I watched opposite-field fly balls look like routine outs and travel over the wall. The Matt McLain example above is very telling. So, what is going on?
What Is Different in the AFL?
I don’t believe the balls are juiced or anything of that nature. A lot of this comes down to the pitch location and movement. We know pitches move differently in Coors Field, and Arizona has a similar effect, but not to the same degree.
Comparing pitch data from the AFL to regular season numbers, most arms lost between an inch or two of movement, both IVB and horizontal. When this happens, location will naturally be more of an issue. Pitches will be left over the plate more, creating a better opportunity for hitters to square up balls.
When a hitter squares up a baseball, it naturally comes off the bat with higher exit velocities. I also wondered if the air in Arizona could allow for slightly faster bat speed, but after more digging, I don’t think that is the case.
So, pitch movement and location likely allow hitters to see the ball better and make cleaner contact. Thus, the exit velocity data is much stronger than we are used to seeing.
Who Were The Statcast Standouts in the AFL?
With all that being said, many of these numbers should be taken with a grain of salt. Surface numbers are relatively meaningless, but the underlying data can be useful. Remember, it is probably best to compare these numbers to peers in the AFL, not regular-season numbers.
The leaderboard below has all the underlying data you could want from all Arizona Fall League hitters.