Posted by Andy on July 23, 2010
These days, each team throws an average of 146 pitches per game, up about 11 pitches per game from 20 years ago. Click through for data and discussion.
This simple plot shows the average number of pitches thrown per team per game each year since 1988.
Complete pitch data goes back to just 1988 so that's why this graph doesn't go further back.
In 1988, teams averaged 136.2 pitches per game. In 2009, it was 147.4, an increase of 8% over the 21-year period.
I generated this data by multiplying two numbers together--the average pitches per plate appearance and the average number of plate appearances per game. (The links are to the B-R pages where those data can be found.)
The average pitchers per PA has gradually increased since 1988. (I showed some of the data in this post and will show the rest of it next week.) In 1988 it was 3.59 pitches/PA and in 2009 it was 3.83 pitches/PA. That's a 6.7% increase itself.
The number of plate appearances per game generally follows overall offensive levels in MLB. That makes a lot of sense if you think about it--every time a guy scores a run, that guarantees another plate appearance in the game. While he's up at bat or on base, there is the potential that he will become an out, but once he scores that out will have to come against a future batter or baserunner. If you click on the link I provided above for average PAs per game, you can read down the column and note how it's changed. Just look at 1968 vs 1969. PAs per game had plummeted through the 1960s all the way down to 37.17 in 1968. Then the mound was dropped for the 1969 season, offense went up, and plate appearances rocketed up to 38.07 per game.
Some random thoughts about the number of pitches per game increasing:
- This affects the length of games, of course. With 8% more pitches, games will take at least 8% longer. Factor in the fact that more pitchers are used per game and the additional pitching changes mean that games are longer by more than 8%.
- In 2009, starting pitchers averaged 95 pitchers per game. In 1988, it was 96 per game.
- Relievers threw 40 pitches per game in 1988 and 52 pitches per game in 2009. (I got those numbers through simple subtraction of the other numbers in this post.) That's a 30% INCREASE.
- Using the PI Pitching Game Finder, I discovered that there were 7,331 relief appearances in 1988 and 14,239 relief appearances in 2009. Normalizing by the number of games in each season (6th column here) that works out to 1.75 relief appearances per game in 1988 and 2.93 relief appearances in 2009. So that's a 67% increase in relief appearances.
- Therefore, relief pitchers are actually throwing fewer pitches per appearance these days than they used to, even though relievers in total are throwing more pitches. (Simply put, there are more relievers these days but they throw fewer pitches per appearance--keep in mind this doesn't necessarily mean fewer pitches per plate appearance.)
It all smacks of a weird sort of inefficient efficiency. Sure, having pitchers throw fewer pitches per appearance more protects their arms, but that also means that you have more guys warming up and guys making more frequent appearances. In the end, I'm not sure pitchers actually have a lighter workload.