A Mild Aussie Summer

So Grant Balfour's Aussie heat was registering about as hard as James Shield's on Thursday night. Lets take a look at how the drop in Balfour's velocity has declined this year and try to find some answers to the following questions:

* How much of the decline can be attributed to the Trop gun?

* Does the number of days rest affect how high the fast ball registers?

* Does the number of pitches thrown in the previous outing affect Balfour's fireball?

* Does greater velocity have an impact on control?

* What effect does the inning and score margin impact Balfour's fastball?

* Does Balfour's velocity tail off in extended outings?

First, let’s take a look at Balfour's home and road splits to test for the variance on the Trop's speed gun. We will look at the performance in away games at Boston (2), Oakland (2), Baltimore (2), New York, Seattle, and Minnesota to generate the average of Balfour's average velocity in each outing and the minimum-maximum range of average velocities. We will do the same for the average, minimum and maximum of Maximum Fastballs (hardest thrown pitch of each game). We can compare that to the same statistics for the games at the Trop. Its important to note that each game is receiving equal weighting regardless of the number of pitches thrown. The complete table of games, as well as split tables is available at the above referenced link. The study provides the following data:

The average velocity at home has been 1.49 MPH slower than on the road. The average maximum fastball registered 1.36 MPH slower at the Trop. The Trop gun is slightly less than 1.5 MPH slower than the average park the Rays have played in to date.

In order to effectively measure for variable trending is to use a static gun so we will only use the home games for the purpose of this analysis. If we sort by average velocity this is what the first table looks like:

As you can see, the three games where he pumped the most strikes there was a direct correlation to a slower velocity. Not surprisingly his K rate was higher when he was throwing harder, but so were the walks. In today’s game while there were no walks, there was a hit batsman.

Lets take a look at another set of variables including the inning entered, score margin at the time of insertion, WPA, # of days rest prior to appearance, and the number of pitches in the previous outing::

Balfour has a slight trend of throwing harder in the late innings of close games. Until today’s game he seemed to throw slower following extended prior outings. He also had been slowing down in May compared to April until today. With all the recent coverage of the Ray’s pitching staff’s decline in velocity, I’m curious if there was pressure to recalibrate the gun before today’s game. Or perhaps Balfour’s early season control issues caused him to hold back a little until he felt in better control of his fastball.

Matt Garza averaged 92.29 and topped out at 94.6 today compared to 90.68 and 93.3 in his previous home start. I would not discount the likely scenario that the gun was recalibrated prior to today’s game as both pitchers were about 1.5 MPH north of usual.  

What conclusions can you draw? As a reminder, the complete table of all variables is published for further study at Balfour's Velocity