Brian Johnson’s Curveball Has Been Key in 2018

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Brian Johnson has been a very pleasant surprise this season, ceasing opportunity after opportunity. You see, Johnson was not supposed to be in the starting rotation. In a perfect, healthy world, he would not have even gotten the chance. Inevitably, though, pitchers get hurt and the Red Sox rotation is no exception. Johnson’s been the depth guy, answering the call whenever a rotation injury arises.

In total (between the bullpen and rotation), the southpaw has pitched 83 innings to the tune of a 4.12 ERA and 4.27 FIP. He is striking more batters out than he has in previous seasons with a respectable 8.13 K/9. This has aided him to what can be described as a fine season for the Florida Gator alumni.

From a run prevention standpoint, he has been much superior as a starter with a 3.63 ERA compared to a 4.94 ERA as a reliever. Oddly, and perhaps intuitively, this seems to be the byproduct of random variance more than anything. His FIP as a member of the rotation is 4.79 while his bullpen FIP is 3.41. Since FIP is a batter predictor of future ERA, yeah, this matters.

Nevertheless, Johnson has done well in his hybrid role and a lion’s share of the credit has to be given to the success of his curveball, the good ol’ Uncle Charlie.

This season it has irrefutably been his best pitch, with a 6.4 pitch value over at Fangraphs. Pitch values, while imperfect, attempt to quantify how many runs a pitcher’s offering is worth. It is a good tool to refer to, but pitches work in sequence with one another so it is hard to put an absolute value on them. Still, his fastball has a score of -5.4, which makes sense given its velocity, and his slider a -3.9. His changeup has a positive score (0.3), yet he has thrown that less than two percent of the time this season.

The curveball seems to be the pitch that has helped him the most because it is his best weapon. According to Brooks Baseball, the lefty has thrown it 403 times this year, which trails only the four-seam fastball in terms of usage. In terms of percentage, he throws the hook about 30 percent of the time, so hitters understand it is utilized quite frequently. Regardless, they have failed to do much with it this season, mustering a .209 batting average and .287 slugging percentage off the curve.

It is a big groundball generator with a 55.81 GB/BIP, meaning it induces a healthy share of weak contact. Not only that, but the curveball yields quite a few whiffs as well. In fact, it has a 22.91 whiff/swing, which is only behind his slider in this category and it is a marginal difference.

He uses it much more often against right-handed hitters than left-handed ones. Johnson’s thrown the curve 34 percent of the time against right-handed hitters and 14 percent of the time against left-handed hitters this season. With his same-sided counterparts, he prefers the slider.

Anyway, yeah, right-handed swingers should expect to see the big breaking ball more than other-handed comrades. He particularly likes to use it in two-strike counts against righties, hence, the aforementioned uptick in K/9. It all comes back full circle.

Johnson’s featured the curveball 42 percent of the time against right-handed hitters when they have two strikes on them. That’s a significant jump.

Here’s his curveball zone profile for this season, courtesy of Brooks Baseball.

That is decidedly where you want to locate a curveball. He rarely ever leaves anything up or even over the middle. This exemplifies the extraordinary control he has on the pitch, as he literally paints it down almost every time. It most appears down below the zone or in the lower third, for the most part.

The Uncle Charlie has above-average vertical movement, getting more bite than an average curveball. That’s probably helped him keep it down, because he would have to release it pretty high to have it wind up over the middle.

Lastly, I would like to show you a quick video, via MLB.com, of Brian Johnson and the curveball.

This at-bat perfectly encapsulates his curveball usage. Justin Smoak, a righty, is at the plate with two strikes. He sets the pitch up down and away, and the execution is flawless. Smoak swings and misses on the big hook and Johnson gets out of the innings.

For a pitcher with mediocre velocity, the curveball is instrumental towards his success at the highest level of pro baseball. It has been filthy all season long and has been the biggest reason why Brian Johnson has performed as well as he has this year.