Do More Foul Balls Really Unnerve a Pitcher – Part 2

After some comments on the last blog post (“Do Foul Balls Really Unnerve a Pitcher”), I went a little deeper and looked at the number of foul balls for a fixed number of balls and a two strike count. The conclusion from just looking at the number of foul balls was that it appears that an increased number of foul balls unnerves both the pitcher and the batter. Looking at the number of foul balls based on the count reinforces this conclusion.

Batting Average

Based on seasons from 1988 – 2009, the batting average by number of foul balls and the place in the count is shown below.

As the number of foul balls increases for a fixed ball/two strike count, the batting average increases consistently. The batting average increases between 17 and 50 points over the zero foul ball batting average. It is possible that pitchers actually can become frustrated because they are unable to put the batter away early. The longer the batter stays alive, the more likely it is that they will actually get a hit.

Even though the batting average increases as the number of foul balls increases, the highest it reaches is about .250. The batting average is significantly lower for two strike counts with a fewer number of balls. This points to the unnerving of the batter with the overall lower batting average, and also with the decreasing batting average as the number of balls decreases.

There appear to be a number of factors influencing the result of the at bat, including whether the pitcher is behind or ahead in the count, as well as how long the plate appearance continues. The closer either the pitcher or batter is to losing the at bat, the more the pressure appears to increase.

On Base Percentage
The on-base percentage shows the same trend as the batting average except for the 3/2 count.

For two strike counts with two balls or less, the on base percentage increases as the number of foul balls increases. The amount that the OBP increases over the 0 foul ball count is about 17 to 50 points as well.

For the 3/2 count, however, the on base percentage increases by about 23 points for one foul ball and then stays fairly level as the number of foul balls increases. This is due to the fact that the walk rate for a 3/2 count is about 30% and remains consistent regardless of the number of foul balls. For the 3/2 count, batters end up on base in nearly one out of every two plate appearances.


Strikeout Rate

The strikeout rate by count and number of foul balls tells a similar story of the pressure increasing on both the pitcher and batter.

As the number of foul balls increases for a given count, the strikeout rate decreases. The longer a batter is allowed to hang around, the more difficult it is for the pitcher to put the batter away. This is also shown by the fact that as the number of balls increases for a two strike count, the strikeout rate decreases as well.

Data Source: http://www.retrosheet.org/

Do More Foul Balls Really Unnerve a Pitcher?

I am traveling in San Diego this week, and I have the chance to go see the Padres play the St. Louis Cardinals this evening. Jon Garland gets the start for the Padres. In an interview with Corey Brock from mlb.com on Monday, Garland was asked about his reaction to Phil Hughes enduring 41 foul balls on last Saturday against the Mets, which was the most since Garland’s 42 foul balls in 2005. Garland was partially quoted as saying that “allowing so many foul balls can be unnerving for a pitcher.”

I took a quick look at some data on the number of foul balls in an at-bat and analyzed the ultimate result of the at bat to determine if batters have more success if they are able to keep the at-bat alive longer by fouling off more pitches. The answer is that it seems to be unnerving to both the pitcher and the batter.

Batting Average

I looked at the batting average based on the number of foul balls in an at-bat using the 2005 – 2009 seasons. The batting average is shown below.

Number of Foul Balls - Batting Average
0 - .295
1 - .230
2 - .208
3 - .217
4 - .228
5 - .228
6 - .229

The batting average drops by between 65 and 87 points after just one foul ball. This suggests that as a batter fouls off more pitches, he is less likely to successfully get a hit. This could perhaps be because the batter becomes a bit “unnerved” or frustrated after fouling off a few pitches. This unnerving also be seen in the strikeout rate increasing as the number of foul balls increases.

Number of Foul Balls - Strikeout Rate
0 - 9.5%
1 - 26.5%
2 - 33.0%
3 - 30.3%
4 - 27.7%
5 - 27.2%
6 - 26.4%

The strikeout rate triples as the number of foul balls increases from 0 to 2 or more. This could actually increase the confidence of the pitcher, knowing it is easier to strike the batter out.

On Base Percentage

The on base percentage of a batter as the number of foul balls increases is shown below.

Number of Foul Balls - On Base Percentage
0 - .359
1 - .296
2 - .286
3 - .316
4 - .337
5 - .350
6 - .343

The on base percentage decreases as a batter fouls off one or two balls, but then begins to increase with the third foul and ends up near the on base percentage for the 0 foul on base percentage level. This suggests that as a player fouls off more pitches they are more likely to end up on base. The obvious reason for this is that as there are more pitches thrown, it is more likely that the pitcher walks the batter. The rate of batters either walked or hit by a pitch by the number of foul balls is shown below.


Number of Foul Balls - Walk Rate
0 - 9.9%
1 - 8.7%
2 - 10.0%
3 - 12.7%
4 - 14.2%
5 - 16.0%
6 - 14.8%

The walk rate increases from 10% to as high as 16% as more pitches that are fouled off. This could be some evidence of the “unnerving” of the pitcher.

It seems that as the stress of any sports situation increases, nerves can possibly come into play. As a batter and a pitcher get deeper into an at bat, nerves can play a part on both sides.