Pace Stats in Baseball and Tennis

We have heard a lot recently about the growing length of a baseball game and there has been some discussion in MLB about possibly moving towards a time clock where a pitcher has to pitch within a specific number of seconds. Pace is also an issue in tennis — in women’s tennis, a server is supposed to serve within 20 seconds of the end of the previous point. In this post, I’ll summarize some data I collected about server pace from the recent Australian Open and then explore pitcher pace data using the Pitch F/X data. (A couple of years ago I dissected the total length of a baseball game using similar data.)

Tennis — Serena Williams and Maria Sharapova

I watch a lot of tennis and it seems that Maria Sharapova has a very deliberate style of serving. I would think that this style might translate into a longer time to serve. To check, I used a timer to measure the time-to-serve for all points played during the first set of the recent match between Serena and Maria at the Australian Open. In the graph below, I plot the pace data against the game number for both players and add a horizontal line corresponding to the 20 second rule. From this graph, we see that although there is some variation in pace, Serena tends to average 20 seconds after the end of the previous point. In contrast, Maria seems to average more like 25 seconds. It is notable that Maria was especially slow in Game 10 which was tense and determined the outcome of the first set.

Baseball — Pitcher Pace Stats from a Week in the 2015 Season

It is interesting that MLB experimented with a 20 second rule in baseball in the Arizona Fall League in 2014. That raises the question — what are typical times between pitches in 2015 baseball?

In the pitchFX data, there is a time stamp that records the time of every pitch and one can use this data to record the times between pitches. One has to be careful in working with this time data. First, we don’t care about the time between pitches of different plate appearances and there are other reasons for a “slow” time to pitch — perhaps there is a pitcher-catcher dialog or something else happens that delays the time until the next pitch.

Anyway, here is what I did (all of the R code can be found at my gist site if you want to see the details):

• I used the scrape function from the PitchRX package to download all of the PitchFX data for the week September 5 through the 11th.
• From the time stamp variable, I computed a new variable that was the number of seconds past midnight.
• For a specific pitcher, I wrote a function that computed the difference in the time between pitches in the same plate appearances. If there was only one pitch in the PA, then I would not be able to measure the pace variable.

Here are histograms of the time between pitches for eight pitchers. Just like the tennis pace data, these times tend to be right skewed with occasional large values. So I think a median instead of a mean is a good measure of “average” — I have graphed the pitcher medians using green lines and the 20 second value with red lines. We see Justin Verlander and Joe Kelly are relatively slow in delivering pitches and Wade Miley seems to be relatively fast.

I collected all of the pitchers with at least 100 time measurements during this week in September. The following graph shows the median pace of all pitchers, arranged from fastest to slowest. We see a majority of these pitchers have an average pace exceeding 20 seconds. Also I think it is interesting to see the large variation in average pace in the pitchers in this group.

I think MLB needs to explore the time of game issue and think of possible rules that might help to decrease the game times and make the game more enjoyable for its fans. A first step in this exploration has to be a careful examination of how the current game progresses in time and a good exploration of the data will be helpful towards that goal.