Air Density Report w/ @SyraCuseeee – 9.7.17


In this article I will break down the top teams and players that are affected the most by VMI and ADI today.  Many of you might ask what is VMI and ADI is so below I have written a brief description of what they mean and how they affect baseball games.

Air Density Report w/ Cuse

Visual Memory Index aka VMI in baseball is used to track how players perform under different air density’s. The easiest way to explain this is that depending on the weather temperature, humidity, or air density the batters swing will be affected.  You might ask yourself how is that possible?  Have you ever tried to swing a bat in the winter compared to a humid summer day?  It’s not the same and VMI tracks each batters muscle memory to various weather conditions.  A batter’s muscle memory takes time to adjust to certain weather conditions.  When taking VMI into effect I avoid teams or players with a number less than -5 which simply can be explained as they haven’t been hitting pitches with the type of movement that they will face on that day.  As far as what’s good for teams or players, I try and target +5 or greater because they will be used to pitches with high movement and their Visual memory will be good.

Air Density Index aka ADI is very simple to explain.  It’s a scale that goes 0-100 and is affected by three things (Elevation, temperature, and Humidity).  The Air Density is important in baseball because it will let you know how much movement the baseball will have in that ballpark on that day.  The higher the ADI the more movement on the pitch.  Typical 60 is the number people use to decide if the pitcher’s movement will be good or bad.  The lower an ADI is from 60 the less movement the pitchers ball will have and the higher it is from 60 will show the increase in the pitcher’s ball movement to the batter’s eye.


Todays Top Pitchers per VMI/ADI

Clayton Kershaw- The Rockies get to experience the Coors hangover tonight and their team VMI certainly shows it at -18.47.  If Kershaw has no limitations its hard not to love him tonight versus the Rockies.  In 336 AB versus Kershaw the Rockies have struck out 100 times with a .220 avg.

Aaron Nola/Tanner Roark – The Nationals have a team VMI of -6.90 and the Phillies aren’t far behind with a team VMI of -3.67. It’s expected to be in the mid 60’s today in Washington with a ADI of 67.97 so both pitchers are in play

Corey Kluber – The White Sox don’t have a terrible VMI but the weather in Chicago will be great for Kluber tonight (66.74 ADI)

Other notable pitchers I have minimal interest in but have a good VMI/ADI vs their opponent are:

Jameson Tailon and Tyler Mahle


Top Teams to use for hitting per ADI/VMI

  • Twins/Royals – This is the only game on the short slate with both teams having a small positive VMI. The weather is changing everywhere and we need to understand that this is going to limit our options for great hitting conditions.