Slow Pitches in the Major Leagues

I have always been fascinated by the slow pitch in baseball, especially the Major Leagues. In a league where 95 MPH fastballs are not unusual, and velocity is important, some pitchers throw pitches in the 60s to unsuspecting batters. I wanted to look at why pitchers might do so and whether or not this is an effective strategy.

Not counting intentional balls or pitchouts, there have been 32323 pitches since 2008 tracked by Pitch F/X thrown under 70 MPH. The clear leader in slow pitches thrown is Tim Wakefield, as over 85 % of the pitches he threw from 2008 to the end of his career were below 70 MPH. Wakefield was well below average in effectiveness over that stretch, but was still an above replacement pitcher.

By far the most common pitch thrown under 70 MPH is the curveball. About 68 percent of pitches thrown under 70 MPH are curveballs (21982 times) and this doesn't include the 509 eephuses or the 231 knuckle curves.

The eephuses are slower at 59.27 MPH on average, while the knuckle curves under 70 average about 67.89 MPH and the curveballs 67.8 MPH. Strangely, there isn't much of a difference between the way the average eephus and slow knuckle curve is located, but the average slow curve is thrown much lower (the entire graph is the strike zone).

When you break the curveballs down by 5 MPH velocity ranges, we see that the slowest ones are located higher while the "harder" ones are located lower:

This explains the difference in eephus and slow curve locations, but not really the high knuckle curves. 8432 of the pitches under 70 MPH are knuckleballs, mostly from Wakefield. I won't look further at them because I plan on looking at knuckleball locations a little bit more in a future post.

So is the slow pitch more effective than a normal pitch? Here are how the slow pitches break down:

2980 whiffs 9.2 %

5954 contact plays 18.4 %

204 home runs .63 %

Compared to league average (just using 2013 for league average for our purposes), the slow pitches actually have a slightly smaller home run rate (by about .03 %) and a league average whiff rate. They also had a .2 % smaller contact rate. So the slow pitches seem to be slightly better than a league average pitch, but probably not significantly. The only thing you can complain about them is that they are harder to throw strikes. The slow pitches have been strikes 61.33 % of the time, while 2013 league average is 63.53 % (63.38 % for relievers, 63.61 % for starters).

What about pitchers that throw a lot of slow pitches? After all, throwing a slow pitch seems to be about deception and tricking the batter. If a pitcher throws a lot of slow pitches, then wouldn't the effect wear off?

This is where looking at Wakefield and others can be helpful. Unfortunately, Wakefield is the only one with a significant amount of pitches with over 50% slow pitches. In fact, only Daniel Herrera and Charlie Haeger are over 20 % with a significant amount of pitches.

With Wakefield, you knew what was coming. He was going to throw the knuckleball, and then another knuckleball, and then a few more. Here are his pitches under 70 MPH broken down by result:

8158 pitches

1771 contact plays (21.7 %)

73 home runs (.89 %)

718 whiffs (8.8 %)

Wakefield was below average across the board with his slow pitches, not surprising considering that he was a below average pitcher and featured the slow pitch heavily. Looking at the two most prominent non-knuckleball examples may be more helpful though.

Herrera:

418 pitches

107 contact plays (25.6 %)

2 home runs (.47 %)

62 whiffs (14.8 %)

I guess since it was a screwball, it isn't surprising to see weird results. He gave up a lot of contact, but at the same time got a lot of whiffs and still didn't give up home runs with it.

Justin Duchscherer:

420 pitches

70 contact plays (16.67 %)

52 whiffs (12.38 %)

3 home runs (.71 %)

The results here are almost as weird as Herrera's. Duchsherer gave up less contact than average with his slow pitches, getting more whiffs, but also giving up more homers (even though he pitched for Oakland, who plays in a pitcher friendly park).

Randy Wolf and Dave Bush are two more pitchers who featured slow curves more than 15 % of the time. Wolf had a well below average whiff rate with it, and a slightly lower than league average home run rate. Bush had an above average whiff rate and a slightly above average home run rate.

What I was really interested in was guys who have good stuff, but still throw the occasional slow pitch. Yu Darvish is probably the best example, getting up to 97 MPH with a fastball with one of the top sliders in baseball, and also throwing an occasional curveball in the 60s.

On a whole, Darvish is better than league average at limiting homers (.57 %), much better at getting whiffs (12.2 %), and gives up less contact than average (15 %). He has thrown 198 pitches under 70 MPH, all curves, about 3.55 % of pitches thrown. They still have an above average whiff rate (10.1 %), but is below his average. He has given up 3 homers with them, a well above league average rate, but gives up contact with it just 11.1 %, much less than league average or his average rate. So for him, it isn't a pitch he misses a lot of bats with, and he has gotten burned with it, but it is thrown mainly as a shock pitch, an attempt to get a called strike. It is a pitch on average, he throws arm side, and about equally high and low. He is trying to throw it for a strike intentionally, just to steal an occasional strike. Considering the rest of his pitches, it is risky.

Vicente Padilla is another example of a guy who throws hard but also occasionally throws a really slow pitch (and ironically, he went from the MLB to the NPB, where he still throws the slow pitch). Sometimes labelled as an eephus and sometimes labelled as a curve, it is more of an aggressively slow pitch than Darvish's, averaging 58.3 MPH versus Darvish's 67.1 MPH. The pitch had a laughable whiff rate, short of 3 percent, but he gave up contact with it two percent less than average and only gave up 1 homer in over 400 pitches with it. Perhaps even more dramatically than Darvish's Padilla's slow pitch was designed as a take pitch for a strike. Padilla locates his slow curve equally arm side as Darvish, but a little higher. It isn't supposed to generate swings, it is supposed to just fall into the strike zone while the hitter stares at it.

Zack Greinke's slow curve is a little different, as his home run rate with it is low, but his whiff and contact rates are high. It is designed to be swung at, and not surprisingly, it is thrown glove side and arm side about equally, and in the low part of the strike zone on average. It is thrown about .3 MPH harder than Darvish's, so it is a slow curve, but he throws it like a classic curve.

There are also some unique pitches such as Yoshi Tateyama and Herrera's screwball/changeups. Herrera located low in the zone on average about equally glove and arm side. Tateyama on the other hand, has both a screwball and a curveball that he throws under 70 MPH. His curve is located arm side and a little lower than the middle of the zone on average. It is clearly a take pitch, with well below average contact and whiff rates. His average screwball on the other hand, is located slightly lower, and so far arm side on average that it isn't in the strike zone. It is more of a contact pitch, getting hardly any whiffs, and a slightly higher than average contact rate.

I count seven other pitchers with two different pitch types thrown under 70 MPH at a significant amount. R.J. Swindle a slider in the high 60s with a curve in the 50s. Mike Mussina change and knuckle curve both in the high 60s. Donovan Hand has a few changeups in the high 60s to go with his high 60s curveball.
Charlie Haeger has a few high 60s curves to go with his knuckleball. R.A. Dickey is a similar story (he has three if you include the eephus and curve differential in the tags). Wakefield had a few 4-seam fastball tags under 70 MPH, along with his curveball and knuckleballs. Dallas Braden threw an occasional slow curve to go with his unusually slow change.

There were also some obvious errors, such as a 4-seam fastball by Frank Francisco and a moving fastball by John Danks. Some of the really slow changeups, including some thrown in the 40s, are really hard to believe (especially one thrown by Radhames Liz, someone who can throw 100 MPH with his fastball). 

So the slow pitch can be effective, and it can be used in different ways by different pitchers. It can be an interesting tool to have, but it doesn't guarantee whiffs. Personally, I thought the home run rates and the whiff rates would be higher than they were.