Zack Greinke on Pitching Inside

After we finished talking about his changeup and what he learned from Felix Hernandez, after we finished talking about command for the Hardball Times Annual, after we talked a little about his slider and his sinker, after we talked about a few hitters, even after I’d said goodbye and shook his hand, Zack Greinke hovered. He wasn’t done. He had noticed something about pitching inside and wondered if the numbers agreed.

It’s probably best to let you into his mind, and then try to unpack the parts.

“I noticed that when you throw away to people, they hit the ball hard,” the Dodgers’ pitcher said, “But they get out a lot more often, too. If you come in to them, they don’t hit the ball hard as often, but somehow they find a way to get hits more often. They’re getting hits more often inside even though their better swings are away and they’re hitting the ball hard more often away. I think they hit a lot of harder fly balls but most guys don’t have enough power to hit it over the opposite field defender’s head. A 300-foot hit is an out most of the time. Inside ground balls, there are so many more places you can hit that ball. Some guys can inside out it, some can hit it up the middle, some guys can roll over it and go down the third base line. You can hit it anywhere. But the outside pitch?”

There’s a lot there, so let’s take it line by line.

“I noticed what when you throw away to people, they hit the ball hard.”

Thanks to Daren Willman at Baseball Savant, we can check out an exit velocity heat map for the strike zone. Let’s focus on right-handers vs right-handers from here on out, just so we can easily see inside versus outside. Looks like Greinke is right:

Low and away and low and inside are different beasts, but it’s probably somewhat safe to assume that Greinke was talking about those quadrants in particular. Not when he’s talking about “inside-out” and “rolling over” on the ball. Low and inside is where you “golf” pitches and “yank them.”

Is it somewhat surprising that exit velocity on high and inside pitches is lower than the outside pitch? The second part is probably more surprising than this part: it’s hard to hit a ball hard when you are squeezing your hands in. As Joey Votto admitted, his approach on those balls “majorly zaps power.”

“They’re getting hits more often inside even though their better swings are away and they’re hitting the ball hard more often away.”

This part is demonstrably true. The inside pitch gets hit for base hits more often despite being hit more softly. This is true even if you compare inside off the plate to outside but over the plate, actually.

One thing, though. Those aren’t all squibs. Let’s now look at the isolated power heat map.

Power is better on inside pitches off the plate than outside pitches over the plate, too. So we aren’t seeing the Ducksnort Effect here.

So we’ve observed that batting average and slugging are better on inside pitches despite the exit velocity being worse. What must be happening is that the angles on the hits are different. Take a look at this great heat map from baseball physicist Alan Nathan — if the hits on the inside part of the plate are more varied by angle, you could have more disparate results despite a lower exit velocity.

Maybe Greinke’s last note will help make a little more sense of this.

“I think they hit a lot of harder fly balls but most guys don’t have enough power to hit it over the opposite field defender’s head. A 300-foot hit is an out most of the time.”

This part makes so much sense, and it probably does a lot to describe the purple donut hole in the graph above. You can hit it hard, but if it’s on a trajectory that lands by a defender, that’s still going to be an out.

Let’s bucket balls crudely by batted ball distance to check out how 300-foot balls do. This doesn’t include angle or velocity, but it does get at Greinke’s statement.

BACON by Distance

Distance	BACON
100-149	0.084
150-199	0.579
200-249	0.601
250-299	0.368
300-349	0.490
350-399	0.881

BACON = batting average after contact (includes homers)
Distance = batted ball distance in feet

Before and after 300 feet, batters have more success. Particularly from 250-299 feet, they have less success. It’s not an automatic out, but it’s an out more often than a ball hit 200-249 feet.

So. Do hitters hit balls on the outside of the plate 300 feet more often?

If we are comparing middle inside on the plate to outside on the plate, probably not. Those averages are almost identical. But how about high and tight versus low and away? High and tight has the lowest average distance in the zone, and that means, by definition, more 200-250 foot squibs that fall in than do so on low and away pitches. Maybe that’s why the batting average high and tight is better than low and away.

Let’s recap how the evidence does and doesn’t support Greinke’s conjecture. Whether you define “inside” as on the plate or off the plate, medium-to-high inside pitches are hits more often once they are put into play. This is true despite being hit softer than outside pitches. It’s possible that this is because inside pitches are hit to different parts of the parks than outside pitches.

A lot of this lines up with what Joey Votto told us about his approach on inside pitches. Take a look at his 2015 heat map on inside pitches and it’s almost exactly what Greinke is talking about. A few pulled hits, and a few bloopers, and hot zones in spots where there normally aren’t any defenders.

Naturally, you begin to wonder if there’s any reason to pitch inside. You can see the Zack Greinke doesn’t go there often, and is going there less often this year. Compare his pitches to righties last year (left) and this year (center) to the league average (right).

The traditional train of thought is that hitters will hang out over the plate if you don’t pitch them inside more often. One of the most iconic moments that can be used to illustrate this effect is when Salvador Perez took Hunter Strickland for a double on an outside pitch that he pulled to left center.

Greinke shrugged that play off, with a sense of awe. “He’s probably the only guy who can do that,” the pitcher said. “Most of the time they’ll hit a weak ground ball or fly ball to the opposite field, or a hard one right at a middle infielder.” And the pitcher that gave up that hit? Hunter Strickland told me something very similar. “Hats off to him. If I’m going to get beat late, I’m going to get beat to the big part of the ballpark.”

This isn’t to say that conventional wisdom is wrong. Perhaps you do need to surprise hitters with inside pitches. It can zap Joey Votto’s power, for instance. Bryce Harper admits that he doesn’t want it there, even if he doesn’t think you can do it three times. The inside pitch still has its place.

But maybe you don’t need to pitch inside so often. Even when they squib the ball on the inside part of the plate, hitters tend to find grass more often than glove.