Jake Arrieta’s One-Grip Multi-Slider

It has one grip, and one sign, but Jake Arrieta’s slider has many shapes. Ask him if it’s a slider or a cutter, and he says it’s both, and more. As much as anything was the secret to his breakout last year, the slider — in its many forms — might be the best answer.

“I can manipulate the velocity, I can manipulate the break, depending on the situation, depending on the hitter, depending on the count,” the pitcher said last week in Spring Training. Look at the movement and velocity of all the balls labeled slider or cutter by PITCHf/x over the past two years, and it just leaps out at you: it looks like he has three sliders.

Each of the sliders has a more specific use. “If I’m trying to get up under a lefty’s hands, I’ll elevate it, giving the appearance of an elevated fastball, something that hitters like a lot, but then you get that four to six inch breaks into the lefty, and by the time they commit, it’s too late,” Arrieta said of throwing a more cutter-like slider against lefties.

Let’s return to the graph from above, adding a filter for batter handedness. Arrieta prefers more horizontal movement against opposite-handed pitchers, and less drop — that top portion of the graph seems, at least relatively, to be populated with floating cutters in on the hands of lefties.

“If I’m going for a swing and a miss late in the count against a righty, I’ll increase the break, maybe decrease the velocity to 87-88, and go for more of a slider break,” said Arrieta. You can see that he regularly increases that break against righties with two strikes in the table below, which shows his slider movement and velocity by the number of strikes in the count for 2013 and 2014 combined.

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StartStrikes	Data	Total
0	Average Velocity	89.39
	Horizontal Movement	2.72
	Vertical Movement	4.03
1	Average Velocity	89.30
	Horizontal Movement	2.74
	Vertical Movement	3.59
2	Average Velocity	89.19
	Horizontal Movement	2.93
	Vertical Movement	2.68
Total Ave Velocity		89.29
Total Ave Horiz Move		2.79
Total Ave Vertical Move		3.45

There’s been some change in this table over time, as Arrieta has become more comfortable manipulating the pitch. Re-run this table with 2012 included, and the differences are smaller in both velocity (no difference) and movement (.8 inches drop difference from no-strike to two-strike slider). The pitcher attributed it to “really understanding my body.”

And getting into better counts, of course. The best command of his career has allowed him to use the slider more often. “I always had the breaking ball I have now, I just didn’t have the command of my fastball to put me in the position where I was ahead in counts, to be able to do different things with it — to be able to throw it beneath the zone for swings and misses, to be able to utilize it early in the count for strikes — it all starts with command,” he said.

But Arrieta does this all with one grip. And the mechanics aren’t that different. “I spin the ball the same almost every time,” he said. “It’s just grip pressure, effort on the pitch, all of that.”

Changing arm speed can be tricky for a pitcher, though. “Not so much arm speed, but effort with the lower body,” Arrieta confirmed. “You’ll hear a lot of old-timers talk about dragging your back side on a changeup, to deaden it, or decrease the velocity, It’s a similar thought process with the cutter or slider, when I decrease the speed. The appearance is exactly the same to the hitter, same arm speed, just a little less effort with the lower body.”

It’s virtually impossible to catch with the naked eye. Below are two sliders from Arrieta to Matt Holliday in his last start in 2014. The one on the left came with zero strikes and went 92 mph. The one on the right came with two strikes and went 88.8 mph and dropped 4.5 more inches.

Tough to see a difference, except that one pitch is bendier and slower than the other. If this seems like a tough thing to do, Arrieta shrugs. “You can do it with all your pitches,” he said. “It’s something that’s vital. Going from a 92 mph cutter to an 87 mph slider — that disrupts the timing of the hitter. Strikeouts are great, but so is a first pitch ground-out or pop-up to the infield.”

His new catchers will figure out when each type of slider is coming, just as Welington Castillo did last year. The pitcher is sure they can handle it. “It’s just one sign.”

One sign for many different pitches.