When is a Swing Path Too Much?

The following nerd talk can be blamed on Ozzie Albies. Currently, he’s on the IL after needing surgery on his broken foot but plans on an August return. While digging through his stats, I was not sold on him being an early-round difference maker. Over the past two seasons, he just had a .255 AVG after it was at .279 in his first four seasons. One obvious change was that he has really started going for flyballs with his Flyball Rate (and Launch Angle (LA)) heading up.

What I wanted to know if Albies has changed his swing for more power and a lower batting average should be expected going forward.

To find the values, I had to do some manipulation of the public StatCast data. I don’t like how it’s currently being provided, so I needed to make a few adjustments.

First, instead of the 95 mph cutoff for the Hard Hit rate (used by BaseballSavant.com), I prefer 102 mph based on this Twitter thread I had with Jon Anderson.

Okay minimum exit velo at 26-30 degrees to reach .500 AVG and 1.500 SLG

2019: 98 mph
2020: 98 mph
2021: 100 mph
2022: 102 mph

— Jon Anderson (@JonPgh) May 20, 2022

A batter’s swing path is the point where they create the hardest contact. The theory behind this concept can be found in these two articles. The value is a by-product of the Hard Hit query. Both of the values can be found in this BaseballSavant search.

The key with this information is to find the sweet spot of getting enough air under the ball for line drives and home runs while at the same time not popping up for some easy outs. Here are six graphs that will get us to a simple rule. If you don’t want to be overwhelmed by the graphs and numbers, feel free to jump down to the Conclusions section.

Graph and Math Stuff

For this step, I going to compare the average hitters’ Isolated Power (ISO) and BABIP using the Hard Hit% and Bat Path. I studied all non-pitchers from 2015 to the present who had 50 batted ball events in a season. I’ll start with ISO since the results are cleaner.

ISO vs HardHit% and Bat Path

First, here is a simple table of average ISO and for certain Hard Hit% and Bat Path. I tried to limit the number of empty values here.

To no one’s surprise, the higher and hard a ball is hit, the hitter’s ISO get higher

The deal is that on the right side of the table a change is starting to occur. For the weak hitters, their ISO has peaked and is heading down.

The change isn’t 100% clear, looks to start around 22 degrees.

Looking at the information another way, here is the average ISO grouped just by the Swing Path.

The ISO values peak around 20 degrees and then start declining. The key swing path for power seems to be around 20 degrees

BABIP vs HardHit% and Bat Path

Power isn’t the only factor to take into account So to start out again, here are the average BABIPs for a certain HardHit% and Bat Path.

The image is not as clean as the ISO one, but there is a range of high BABIP under 15-degrees Bat Path and over 15% Hard Hit%

Again, here is a look at the limited results from an upper cut bat path.

Again, not the prettiest image, but all the extremely low BABIP values fall in this range.

And finally, one last graph to show the average BABIP at different bat paths

While there is some curvature to the BABIP graph, it’s flatter from -5 to 20 degrees.

Conclusions

From the graphs and tables, the key to being productive is to hit the ball as hard as possible (duh) with a swing plane of 20 degrees. To get to elite levels, the Hard Hit% needs to be over 20%

Going back to Albies, here are his Hard Hit% rates and Swing Paths over the years.

The change in Swing Path obviously occurred between the 2019 and 2020 seasons. The change wasn’t as obvious since his Hard Hit% was in the low teens. When that rate dropped to 6% this season, all his results tanked. Albies swing path is fine as long as he’s hitting the ball hard.

Besides Albies, here are some other hitters with a Swing Path over 22 degrees but a sub-15% Hard Hit%.