If you watch Sergio Romo hold a ball even for just a minute, it’s obvious how he found the grip for his unique slider. Just like every other part of the Giants’ reliever, his fingers can’t stop moving. He’s constantly fidgeting, so he can’t remember the exact moment he settled on his particular finger placement. He continues that fidgeting when it comes to his craft, really.

To Romo, the slider isn’t maybe as legendary as it sounds when you talk about it as his No-Dot Slider with capital letters. “It’s just different. I don’t really see it as ‘good’ or ‘special,'” he told me. But there was one compliment that meant something to the pitcher at one point.

More than 2000 sliders ago, Romo was a good middle reliever for the Giants as they headed to the World Series. There, he faced Bengie Molina, who had just been traded from the Giants to the Rangers. After the Giants won, Molina gave the reliever “the greatest compliment.” The catcher told Romo that “catching it and seeing it in the box were two completely different things,” and that “if I don’t have confidence in my stuff, I’m a waste of talent.”

“That’s pretty much where my career took off,” said a smiling Romo. And in terms of emotional and mechanical process, the comment was enough to affect change. “Confidence,” Romo comments — and then the willingness to throw the slider as often as possible. Before 2011, Romo threw the fastball more than 50% of the time — he hasn’t done that since, and he hasn’t topped 40% since 2011.

“The way I see my slider — other than different — is that it’s my 95,” said Romo. The slider has become his fastball, and his fastball has become the pitch he picks and chooses. “Just like other pitchers have to pick and choose with their breaking stuff because it’s not their best pitch,” Romo agreed.

The reason it works so well for Romo, though, is that no-dot approach. Most sliders spin around an axis that creates a red dot from the spinning seams. Like this:

Perhaps because of the way Romo grips the pitch with his two fingers separated, or the fact that there’s so much white facing the batter because of the way he holds the seams, or because it’s a very horizontal pitch (with as much horizontal movement as the biggest curveballs) thrown from a low arm angle, there isn’t a tell-tale red dot on his slider.



The grip on Romo’s no-dot slider.

The fact that it looks like a fastball in terms of spin has actually led to a few changes in his approach recently. He’s always had trouble against lefties, and he’s tried a few different things.

Romo’s first response to those problems has mostly been to go to the fastball more. PITCHf/x says Romo throws 60% fastballs to lefties; the pitcher says it was 80% sinkers to lefties. But that didn’t work either. “I started to fall behind on lefties because they were seeing like 80% sinkers away, and they could wait for a strike” Romo said, “and the best sinker or slider is a ball.”

Last year was the first time he threw a changeup over 10% of the time, and though the movement on the pitch was okay, it wasn’t the solution. And getting them to swing was the problem. “If it doesn’t look like a strike out of the hands, what’s the point?” asked Romo. The swing rate on his changeup is more than ten percentage points lower than on any other pitch.

So Romo has learned to change the movement on his slider: “I know how to throw a slower one with sink. A shorter one that is harder. A shorter one that isn’t as hard. The front door one. I throw it right at them knowing it’s going to get in there. I’ve learned how to get it down, but I struggle with really hitting the ground and spiking it because of my arm angle.”

If you use the filters, you can see that Romo is throwing the harder, faster slider with less movement to lefties. And though his overall numbers against lefties aren’t much better this year, Romo thinks this could be the key going forward. “I’ve gotten more swings and misses this year from lefties,” Romo said. “When I throw the slider, that shorter one that’s going more down and not into them, they’re not hitting it.”

That’s the strategy behind the improved pitching this year — a new wrinkle on the no-dot.

There are other reasons for being better this year that won’t show up in a PITCHf/x query. When asked if his slider has more bite this year, Romo paused. He almost fell into this answer, but even thinking of whatever it was he was thinking of exactly got him choked up. Gone was the fidgeting, for just a second, and the voice slowed to almost a whisper. “I think maybe the focus has been better this year. I’ve had some rough moments. I shouldn’t say that I’ve been at my best or that I’ve been what my teammates needed at all times out there,” he said of last year.



The slider is back to full health. Thanks to PitcherGIFs for the image.

But things are better now. “It was getting back into the swing of things this year,” the reliever said. “Certain things, personal or not, that may translate or may affect you. Life is life. I’m noticing it in my breaking ball, and my demeanor on the mound. A little peace of mind.”

That peace of mind can’t give back what time takes away. Even a guy that has never seen higher than 93 on the gun is now down to 87 mph on the fastball. “As I’ve gotten older, I’m more 87, 88 and 90 is when I’m feeling good,” he laughed.

And he used to get a little bit of drop on his slider, but as his arm slot has dropped, so has the drop on his pitch. “The number of pitches I’ve thrown, I just can’t [get] the same feel for the same old slot,” he said of that slow change in his mechanics. Since we know release point has a lot to do with fastball rise, it’s no surprise to see this now:

But that arm slot, combined with the no-dot grip, has given Romo a slider with few comps. Take a look at righty sliders that have been thrown at least 200 times, and he zooms to the top of the leaderboard. (Although if you call Corey Kluber’s breaking ball — with virtually the same grip and a similar arm slot — a slider, then Kluber is right there with him on this board with 9.4 inches of horizontal movement).

Other pitchers have their velocity, but when Romo throws his slider, he feels equal. “In my head, I’m throwing 95 with my slider,” Romo said with a self-knowing smile. But he was wrong about one thing. That pitch is good, and it is special.