What can Swing Path and Attack Angle Data tell us about different batters?

Steven Kwan batting for the Cleveland Guardians, CCed by Liscense 2.0

Recently, Baseball Savant unveiled new visualizations and metrics that measure a hitter’s attack angle, attack direction, and swing path tilt. The site and leaderboard can be reached at the link here if you want to check it out for yourself. Here, I will be giving an overview of the new metrics available, highlighting what they can tell us about a hitter, and pointing out a couple players who could potentially stand to make some tweaks to their swing. 

Attack Angle

The attack angle describes the vertical angle of the sweet spot when contact is made. Contrary to some people’s views, there is not a single player in MLB who swings down, or who has a negative attack angle. Some players, such as Jacob Wilson and Steven Kwan, hover close to the 0 degree line, but no one is technically speaking swinging down on the ball at contact. Savant says that the ideal attack angle for a hitter is between 5 and 20 degrees. This ideal point is dependent on timing, however. A pitch hit to the opposite field may have a lower attack angle while a pitch that is pulled will generally have a higher attack angle. This is due to the inherent uphill nature of the swing and bat path. The further out in front, the higher the attack angle in most cases. 

Attack Direction

This is similar to the attack angle but measures the horizontal angle of the sweet spot at contact. The league average is 2 degrees to the pull angle. Swings at 0 degrees will have the sweet spot squared to centerfield. A swing that is 5 degrees to the pull angle will feature the sweet spot more around the pitch while one 5 degrees to the opposite field angle will see the sweet spot behind and still angled that direction at contact. Again, this is timing dependent as the sweet spot works from opposite field angle to 0 degrees to pull angle throughout the swing. However, the average attack direction of a hitter can reveal insights into their approach and potential timing issues that may be occurring. 

Swing Path Tilt

On their page, Savant defines the metric as “measur(ing) the angular orientation of the "plane" of the swing, as compared to the ground, defined by the path of the bat in the 40 ms prior to contact, which approximates a slice of a flat disc in shape.” The lower that this angle is, the flatter the swing will be while higher angles reflect a steep swing. The average for the league is 32 degrees, and most players live around that point. On the flat side, you have players like Alejandro Kirk and Yandy Diaz while players like Riley Greene and Freddie Freeman feature a steeper swing than average. 

Takeaways

While the new metrics and visualizations are purely descriptive and not predictive of anything like an expected stat may be, the biggest takeaway, for myself at least, is the insight that the average fan now has to analyze a player’s timing and swing path as a whole. Because of the nature of attack angle and attack direction being timing dependent, the public sector now has a very interesting opportunity to analyze and better understand the effects that timing has on quality of contact, what attack angles are optimal for each player, and what attack direction is ideal for the individual and their approach. Unfortunately, this is not my strong suit, but I am looking forward to reading the analysis that comes out of this data being made public. I would hypothesize, however, that it will be difficult to make broad sweeping generalizations about what is ideal for all players. Because of biomechanical preferences and limitations, players operate and move in different ways than their peers. This is best represented in the swing path tilt. There are successful hitters at both ends of the leaderboard, just as there are hitters who are successful with lower attack angles and an opposite field attack direction. 

Potential Improvements

The easiest player to highlight with this data is Vladimir Guerrero Jr. While the 500 million dollar man features premium bat speed, he currently has the lowest average attack angle in the league at 1 degree. This could be attributed, at least partially, to his relatively flat swing path tilt which is 6 degrees flatter than league average. While he is still having success at the plate, raising his attack angle a bit could potentially raise his average launch angle and allow him to hit the ball in the air more often. He hits the ball hard already, with an average EV of 92.3mph and a max of 120.4mph, and a raise in his attack angle could allow him to be even more dangerous than he already is. 

Another player to note is Kristian Campbell from the Red Sox. While his rookie season has seen some ups and downs so far, he does a lot of things really well in the swing. His bat speed is above average and he features an 11 degree attack angle which is comfortably in Savant’s prescribed ideal range. However, his attack direction averages 8 degrees to the opposite field, an indication that his timing may be a tad bit late. When drafted, Campbell was highly touted for his bat to ball skills, but the Red Sox made a concerted effort with him in the minor leagues to raise his bat speed and tap into more power. The results have spoken for themselves throughout his career as he has grown his power ability and was seen as a consensus top 5 prospect in the game prior to being called up. The attack direction he is featuring could be a product of his adjustment to Major League pitching, which is definitely to be expected, but I’m sure that the Red Sox are hoping that he can tap into a bit more of the power that he has added at the highest level. This, I would argue, would largely stem from his ability to shift his attack direction and catch the ball a bit more out front. 

As a note to these two potential improvements, I will add that there is certainly a lot more going on in the swing than Savant is able to measure. If Campbell shifted his attack direction to be more towards the pull side, he may see an increase in swing and miss and lose a piece of what made him a valuable prospect. If Guerrero were to raise his attack angle, it could have unforeseen implications that take away from his ability to hit at his highest level. These are purely hypotheses that are meant to show some potential tweaks that could be made to a couple players to unlock some more success.