Throwing and Not Throwing Balls in the Dirt

I was having a conversation with a friend the other day about athletes in other sports who might hypothetically be able to make a decent transition into baseball. It’s something I think everyone’s thought of at least a few times before, and the first thing that came to my mind was that hockey goalies could and would make for good backstops, since they’re highly skilled at keeping things moving quickly from getting right past them. I know, for example, Dan Wilson used to be a goalie, so it’s not a surprise he was also a good defensive catcher when it came to blocking low pitches. It requires pretty obviously the same kind of skill.

Yet, while it’s clearly important for a catcher in the majors to be able to block challenging pitches, it’s also true that, in the majors, there isn’t a lot of spread in skill. Which means there isn’t a lot to be gained by being particularly excellent at preventing pitches from flying by. Last year, by our measures, the A’s were baseball’s worst pitch-blocking team, and it cost them 5.5 runs. The Cardinals were baseball’s best pitch-blocking team, and it gained them 6.4 runs. From worst to best, it’s a spread of about a win, which makes it maybe an unjustifiable thing to be concerned about one way or another.

But pitch-blocking can also have other, indirect effects. Most obviously, it can have an effect on the pitches actually selected to be thrown in the first place. A particularly capable blocker might end up getting thrown more balls in the dirt than a lesser-effective blocker. Not only might the catcher call for more such pitches; the pitchers might throw more such pitches, having a greater amount of confidence in the catcher to block them if need be. Basically, the better a catcher is at blocking, the greater the number of pitch options in all situations. In theory. Because the risk of extra bases is reduced.

To be honest, these are all just words around a sortable table, which is following shortly. I got curious about pitches in the dirt, and I got further curious about pitches in the dirt with a runner on third, since that’s when a wild pitch or passed ball is the most costly. It’s not that tricky a thing to look up — PITCHf/x lets us know when a pitch was a ball in the dirt, and it lets us know when a pitch was swung on, missed, and blocked. Armed with that knowledge, I dug into the 2013 data, postseason included for the corresponding teams. Invaluable help was provided by Baseball Savant.

I wasn’t looking for anything in particular — I just wanted to see what the numbers would say. So, you’ll see a table, broken down by team. The first set of columns shows the rate of pitches in the dirt in 2013 overall, and the number of standard deviations above or below the mean. The second set shows the same data for pitches thrown with a runner on third. The third set shows the same data for pitches thrown not with a runner on third. The final column simply shows the difference between the latter two z-scores. In other words, it shows the teams who threw relatively more and relatively fewer balls in the dirt with a runner on third.

It’ll be easier to say more after the table, so here’s the table.

Team	Rate, overall	z, overall	Rate, 3rd	z, 3rd	Rate, other	z, other	z Diff
Angels	3.1%	0.9	7.4%	0.9	2.6%	0.7	0.2
Astros	3.3%	1.3	7.2%	0.8	2.8%	1.2	-0.4
Athletics	2.1%	-1.4	5.4%	-0.8	1.8%	-1.4	0.6
Blue Jays	2.7%	0.0	6.5%	0.2	2.3%	-0.1	0.3
Braves	2.1%	-1.5	5.5%	-0.7	1.8%	-1.6	0.9
Brewers	3.1%	0.8	7.6%	1.1	2.6%	0.6	0.6
Cardinals	3.0%	0.5	6.5%	0.2	2.6%	0.6	-0.5
Cubs	3.3%	1.2	8.1%	1.5	2.7%	0.9	0.6
Diamondbacks	3.2%	0.9	7.0%	0.6	2.8%	1.0	-0.4
Dodgers	2.9%	0.4	5.6%	-0.6	2.7%	0.8	-1.4
Giants	2.4%	-0.9	5.1%	-1.0	2.0%	-0.9	-0.2
Indians	2.3%	-1.1	4.8%	-1.3	2.0%	-1.0	-0.3
Mariners	3.1%	0.9	7.0%	0.6	2.7%	0.8	-0.2
Marlins	2.4%	-0.8	6.2%	-0.1	2.0%	-0.9	0.9
Mets	2.3%	-1.1	5.6%	-0.6	1.9%	-1.2	0.5
Nationals	2.7%	-0.2	7.0%	0.6	2.3%	-0.3	0.9
Orioles	2.0%	-1.7	4.8%	-1.3	1.7%	-1.7	0.4
Padres	2.7%	-0.2	6.2%	-0.1	2.3%	-0.3	0.3
Phillies	2.7%	-0.2	5.2%	-1.0	2.3%	-0.1	-0.9
Pirates	3.8%	2.3	8.5%	1.9	3.2%	2.2	-0.3
Rangers	2.7%	-0.1	5.5%	-0.7	2.5%	0.2	-0.9
Rays	2.6%	-0.4	5.8%	-0.5	2.3%	-0.2	-0.2
Red Sox	2.6%	-0.4	6.0%	-0.2	2.2%	-0.5	0.2
Reds	2.3%	-1.0	4.5%	-1.6	2.1%	-0.7	-1.0
Rockies	3.0%	0.5	6.5%	0.1	2.6%	0.5	-0.4
Royals	3.5%	1.6	9.4%	2.7	2.9%	1.3	1.3
Tigers	2.8%	0.0	5.9%	-0.4	2.4%	0.2	-0.5
Twins	2.3%	-0.9	5.4%	-0.8	2.0%	-1.0	0.2
White Sox	2.6%	-0.3	6.9%	0.5	2.2%	-0.5	1.0
Yankees	3.2%	1.0	5.9%	-0.4	3.0%	1.5	-1.9

Nobody threw a greater rate of pitches in the dirt than the Pirates. Nobody threw a lesser rate of pitches in the dirt than the Orioles, at just about half the Pirates’ rate. The Orioles and Pirates were separated by four standard deviations, with the league average being about 2.8%.

Interestingly, you’d think the rate might be lower with a man on third, since teams don’t want to give up runs with passed balls and wild pitches. Broadcasts often talk about how, with a runner on third, the ball in the dirt might be off the table. Yet, league-wide last year, 6.3% of pitches with a runner on third were thrown in the dirt. Meanwhile, just 2.4% of pitches not with a runner on third were thrown in the dirt. This might well call for deeper research, but based just on this, teams are willing to risk the ball getting away for the sake of maybe getting more whiffs or grounders. Teams, generally, aren’t worried that the catcher behind the plate won’t be able to stop a low pitch if he knows that it’s coming.

I wondered about teams with different approaches with runners on third. I should say right here that I’ve attempted no corrections or adjustments for pitcher identities. I also didn’t break anything down by individual catcher. But, with runners on third, the Royals threw the greatest rate of dirtballs, and the Reds brought up the rear. In other situations, the Pirates and the Orioles were the leaders and laggards, respectively.

With runners on third, the Royals’ rate was 2.7 standard deviations above the mean. With runners not on third, they came in around 1.3 above, and the difference here of about 1.3 was the greatest in baseball. Implied is that Salvador Perez trusted himself, and Royals pitchers trusted Salvador Perez, even with a runner 90 feet away. At the other end, the Yankees were 0.4 standard deviations below with runners on third, and 1.5 standard deviations above with runners not on third. The difference here of about -1.9 was the lowest in baseball, so either pitchers didn’t trust the catchers, the catchers didn’t want to deal with the chance, this is small-sample-size noise, or a correction is needed to take the pitchers into account. The Yankees still threw twice as many balls in the dirt with runners on third as with runners not on third, but everything has to be considered within the league context.

There’s basically no relationship between the z Diff — the last column in the table — and our pitch-blocking metric. There’s only a very weak relationship between overall ball-in-dirt rate and our pitch-blocking metric. The Pirates were second in baseball in wild pitches, and first in rate of balls in the dirt. The Orioles were 29th in baseball in wild pitches, and last in rate of balls in the dirt. The Cardinals were 30th in baseball in wild pitches while throwing a greater-than-average rate of pitches in the dirt, which speaks to the skill of Yadier Molina. Yet the Cardinals were also relatively more cautious about balls in the dirt with a runner on third. The A’s went the opposite way, even though their catchers were sort of the anti-Molina, on the whole. We can’t tell from this whether it’s better to be more aggressive or more careful with a runner 90 feet away. We can tell that teams pick up their dirtball rates overall even when there’s a runner threatening to score. This might be the opposite of one’s expectation.

As usual, I’m left with plenty of questions and only hints of some answers. That’s the kind of thing that happens when you dive into statistics without a hypothesis to test. This was more exploring for the sake of exploration, and I might choose to run some further exploration down the road. If nothing else, we know that teams as a whole aren’t that afraid of a runner on third, or at least they aren’t that afraid of a wild pitch in the same situation. Better, it seems to have been decided, to keep all the pitches on the table, and maybe make the batter pay for over-aggressiveness. Because at the end of the day, if you’re catching in the majors, you’re probably damned handy with heaters and breaking balls low. Even if you’re Wilin Rosario.