A Summer of Spin Rates (Part 2)

Earlier this week, I wrote about what I’m doing this summer. I promised another article that would focus on the stats and data that TrackMan collects from hitters. This is that article.

Some of the cool things that TrackMan can measure on the hitting-side are exit velocities, launch angles, spin-rates, distance, and hang time.

Out of the those five, the coolest ones are probably exit velocity and launch angle. I will write a bit more about those two. The other three — not so much.

Exit Velocity

Exit velocity (or velo) is the speed at which the ball comes off the bat once the batter makes contact. Exit velocity is measured for hits, outs, errors, and even fouls. Like pitching velocity, a batter’s goal is to attain the highest exit velocity possible. While a high exit velocity doesn’t always guarantee a hit (the ball could be hit directly to where a defender is standing), in general the higher the hit speed the more likely a hit will occur, for the defenders have less time to react. Interestingly enough, the highest exit velocity measured thus far in 2016, a 123.9 mph rocket by Giancarlo Stanton, resulted in a ground-ball double play.

Looking at exit velocities can often tell us if a hitter is poised for improvement, or regression. A batter that records consistently high exit velocities but isn’t hitting well statistically may just have a case of bad-luck where most of his batted-balls are hit directly at defenders. In the near future, it’s likely that some of those outs turn into base hits, thus boosting statistical performance. The opposite can be true too. A batter who is performing well statistically but records below-average exit velocities may be getting lucky in the sense that a lot of his hits are hit poorly, but are finding holes in the defense. In the near future, some of those hits are probably turned into outs by the defense.


Launch Angle

Launch angle is the vertical angle at which the ball leaves the bat. From MLB.com, we can see which batted-ball result is expected at each launch angle:

  • Ground ball: Less than 10 degrees
  • Line drive: 10-25 degrees
  • Fly ball: 25-50 degrees
  • Pop up: Greater than 50 degrees

Intuitively, launch angles make sense when evaluating hitters. Fly-balls hitters, who hit more homeruns and extra base hits, usually have greater launch angles. Ground ball hitters, who tend to hit more singles, record lower launch angles.

Among hitters with the highest exit velocities, Jarrod Saltalamacchia has the greatest average launch angle at 26.5 degrees. Upon closer examination, it looks as though most of Salty’s fly balls have been caught, as he carries a .192/.417/.729 slash line into today. Salty has 23 hits on the year, 12 have gone for extra bases — consistent with the idea that hitters who hit more fly balls also have more extra base hits.

On the other extreme, David Freese has an average launch angle of 2.2 degrees. David has a 3.75 GB/FB ratio, or he hits almost 4 times as many ground balls as fly balls.


Spin rate, distance, and hang time

Similar to pitching, a batting spin rate is the speed of rotation (in RPMs) that the ball leaves the bat. Batting spin rates don’t correlate with exit velocities. Any former baseball player can attest — some of the hardest hit balls tend to have no spin at all, and even will have some knuckling-action. Though, spin rate is needed to hit homeruns. Balls with high spin rates carry more.

Distance and hang time are self-explanatory. Distance being the distance (in feet) from the batters box to the location where the ball lands. Hang time is the time (in seconds) the ball spends in the air once it’s hit.

Nomar Mazara, a rookie outfielder for the Texas Rangers, has the greatest measured distance on a homerun this season — a 491 ft. shot that left the bat at 107.8 mph and at a 26.9 launch angle.




Posted by Jeb

From the great "vacationland" state of Maine. Former D3 baseball player on an underachieving team. Prior: TrackMan with A's. Current: Check Down Sports. Soon: Video with Reds. All-time facial hair lover.

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