Zach Britton’s Ground Ball Rate Defies Comprehension

It wasn’t all that many years ago that ground ball rate was the rage when it came to analytically inclined teams. Teams discovered that pitchers who could generate lots of ground balls generally had success. You don’t give up home runs on ground balls. Most ground balls that are hits end up as singles. Ground balls generate double plays and with increased advanced positioning, ground balls give teams better chances to turn ground balls into outs.

But before long, it became just another tool in the growing toolshed of stats and analytics teams can use to study players. As one pro scouting director explained to me five years ago: Yes, everyone wants to acquire pitchers who have plus sinkers that can generate strikeouts and ground ball outs, but there just aren’t enough of those guys to go around. So you have to find fly ball pitchers who can have success too.

That may be true, but then there’s Zach Britton. If an analytics department was given a large enough research-and-development budget and time to build a synthetic pitcher, Britton would likely be what the quants and engineers would create. He’s quite simply the greatest ground ball pitcher we’ve seen in the modern, stat-heavy era.

This isn’t another examination of why Britton didn’t pitch in the Orioles’ loss to Toronto on Tuesday night. Instead it’s an appreciation of what he has become as a pitcher, which does offer yet another reminder of how shocking it is that he was not one of the seven pitchers Baltimore used.

Britton has been building to this point for quite a while. When he ranked No. 2 in the Orioles’ Top 10 after the 2010 season (and the No. 28 prospect on the Baseball America Top 100 Prospects list), our scouting report flatly declared that Britton had “the best sinker in the minor leagues.”

Now we know that it’s the best sinker in the major leagues. We don’t have accurate ground ball data for Walter Johnson or Bob Feller or Steve Carlton or even Greg Maddux. But for the data we do have, (2002 to present at Fangraphs.com), when it comes to generating ground balls, Britton laps the field. This year, Britton faced 254 batters. Nine of them managed to lift a ball hard enough to get an extra base hit.

A look at the ground ball data shows that much like many other parts of the game, ground ball pitchers have become much more extreme in their skill in recent years. Hard-throwing pitchers now throw harder than they did 10 years ago. And sinker-ballers throwing bowling balls have graduated from tossing eight-pound kiddie balls to the 16-pound Brunswicks.

No pitcher from 2002-2009 recorded more than 5.3 ground balls for every fly ball they allowed. From 2011-2016, at least one pitcher has topped that number every year. The top nine ground ball rates among pitchers with 50 or more innings have all taken place this decade. Early last decade, there would be five or six pitchers who would record three ground ball outs for every fly ball they gave up. This year, there were 13.

But among that group of extreme ground ball pitchers, Britton is at a different level. When the Orioles moved Britton from the rotation to the bullpen before 2014, it allowed him to stop worrying about mixing pitches. Now he generally just throws sinker after sinker. It doesn’t matter if hitters know it’s coming, because it dive-bombs the bottom of the strike zone time after time.

When looking at ground ball percentage, Britton’s 80-percent rate this year is the best in the 14 years of data. It broke the record 79.1 percent rate he racked up last year. There have been only four seasons where a pitcher got ground balls on more than 75 percent of balls put in play against him, and Britton has three of them.

The other top ground ball pitcher of this decade is Brad Ziegler. Ziegler is the old-school ground ball pitcher in the Chad Bradford mold. He is a submariner who is tossing 85 mph sinkers from a very low slot. Britton is coming over the top from the left side with a 96-97 mph sinker. It’s an 80 fastball on the 20-to-80 scouting scale thanks to velocity and movement.

This year Britton recorded 9.14 ground balls for every fly ball. Rangers reliever Sam Dyson was second best in the league with 4.09 ground balls per fly ball allowed. Third-best was Jeremy Jeffress at 3.75. In other words, Dyson and Jeffress are hard-throwing sinker-ballers who stand out for their ability to generate ground balls; Britton is an outlier that defies full comprehension.

And that’s what makes Tuesday night’s decision to leave him in the bullpen so difficult to comprehend. Against a team that relies on home runs and extra-base hits to a large degree, Britton is the pitcher who avoids the game-ending bat-flip home run better than anyone. He just never got the chance to show it.