Jimmy Nelson’s Revamped Arsenal

Last year, Jimmy Nelson was bad. There’s no way around it. He walked 86, plunked 17, both of which were league highs, and posted career worsts in DRA (5.83), FIP (5.12), and WHIP (1.52).  He was making life miserable for himself, and this offseason, he vowed to change. His plan, as he told the Milwaukee Journal Sentinel, was to force contact:

“If you force contact, there’s going to be more hits.” he said. “You just try to cut down on the things you can control, which is walks and hit batters.”

So far, Nelson has lived up to his word. Through his first five starts, he’s shrunk his 4.3 BB9 from 2016 to 3.1 this season, his 5.12 FIP to 4.38, and has only hit one batter.

Further, last year Nelson had six total games with one (or fewer) base on balls. This year, he’s already produced three such games. And, he hit a batter in 14 of his 32 starts last year, but in only one of his first five this season.

Nelson has shown improvement, but there is one problem. Despite his shrinking walk totals, the “more hits” aspect of his promise has also come true. His WHIP still sits at a disappointing 1.53.

Overall, looking at Nelson’s control stats, it’s clear things have changed.

2017 Pitches Ball percentage Strike Percentage Swing Percentage Foul Percentage Ball in Play


Fourseam 27.9 28.4 51.8 23.8 18.8
Sinker 32.3 28.0 46.0 16.7 22.3
Change-up 42.9 25.0 42.9 14.3 17.9
Slider 30.7 23.9 56.8 21.6 23.9
Curve 47.0 30.6 28.6 12.2 10.2
2016 Pitches Ball Percentage Strike Percentage Swing Percentage Foul Percentage Ball in Play


Fourseam 38.3 21.8 49.7 23.2 16.0
Sinker 36.7 23.0 43.8 18.2 21.5
Change-up 47.2 16.7 38.9 16.7 19.4
Slider 37.6 18.3 57.0 25.8 17.2
Curve 44.4 35.0 28.4 10.6 9.3

Every single pitch has decreased in ball percentage and increase in strike percentage Well, except curveballs. With curveballs, it’s been the exact opposite.  In fact, that’s not the only change that’s occurred with Nelson’s curveball in 2017.

In 2016, Nelson used his curveball 17 percent of the time when pitching to left-handed hitters and 8 percent of the time against righties. However, in 2017, while he’s kept his usage of the curve at a relatively consistent 15 percent against lefties, he’s all but abandoned his curve against righties. Since he first introduced his curve in 2015, he’d only thrown 5 or less curveballs in a start three times, but this April, he’s already done that three times and, in total, only thrown three curveballs to right handed hitters.

At first, it was confusing to me why Nelson would suddenly drop the curve. Last year, he’d thrown it for a strike 36 percent of the time, the highest of his four pitches. In a season where Nelson was looking to consistently be in the zone, I figured it would be a valuable asset. But, he also missed the zone with it 41 percent of the time, it produced a whiff rate of only 9 percent, and righties smacked it around to the tune of a .292 average. The pitch proved to volatile to use against righties, especially since his slider, which, in 2016, he threw 32 percent for strikes and 33 percent for balls, limited righties to a .155 average. Pairing his power fastball, which limited righties to a .258 average in 2016, with that slider would presumably breed success in 2017.

Nelson’s curveball isn’t the only pitch that’s undergone a drastic shift. In fact, it’s not even the most drastic of the five in his repertoire compared to 2016:

2016 Fourseam Sinker Slider Curve Change
vs LHH 27% 47% 6% 17% 2%
vs RHH 21% 46% 24% 8% 0%
Total 24% 46% 15% 13% 1%
2017 Fourseam Sinker Slider Curve Change
vs LHH 44% 25% 8% 15% 8%
vs RHH 28% 40% 29% 1% 1%
Total 37% 31% 17% 9% 5%

Nelson has shifted sinker, fastball and change-up tendencies. Last season, he averaged 43.3 sinkers per start and 229 per month but this season he’s only averaging 32.2 per start. Against lefties, he’s switched from sinker to four seam as a main weapon for the first time in his career.

When he first came up in 2014, Nelson could have been considered a sinkerballer, throwing 57 percent sinkers with a complementary 25 percent sliders in 12 starts. Only 15 percent of his pitches were fourseam fastballs.

In 2015, Nelson altered by dipping to 35 percent sinkers and 17 percent sliders, while raising his fastball percentage to 25 and introducing a curveball that took up the final 21 percent.

2015 Fouseam Sinker Slider Curve Change
vs LHH 22% 37% 9% 29% 3%
vs RHH 28% 34% 23% 15% 0%
Total 25% 35% 17% 21% 1%

However, the real theme in 2015 was his shift in breaking ball usage. According to the Journal Sentinel, Nelson (and Taylor Jungman) were encouraged to develop more reliable off-speed pitches to support the hard stuff. Nelson shifted from throwing 25 percent breaking in 2014 to 38 percent in 2015.

This was easily his best season in the bigs, and his 4.11 ERA, 1.28 WHIP, 8.3 H9, and 96 ERA+ all say so. Besides his league high 13 hit batters, which furthered the worry of command issues, the 26 year-old Texan looked promising.

2016 brought another shift. He moved back to his 2014 form by heavily upping his sinker usage and it caused similar control issues. He realized his fastball was a more reliable and controllable pitch that causes more whiffs and less line drives.

This is why I believe we’ve seen Nelson shift so dramatically away from the sinker in 2017. He’s lost confidence in that pitch as a main weapon, and honestly there was minimal reason to have confidence in it in the first place. In 2014, opposing hitters hit .331 against the sinker, in 2015 they hit .311, and in 2016 .315. Even worse, the last two years he’s been unable to throw his sinker for a strike more than 22 percent of the time.

He’s already seemingly ditched the sinker against lefties, but there is a definite argument to ditch it altogether. This season righties are hitting .391 against Nelson’s sinkers, 8 of the 13 base hits, including the only home run, he’s given up have been off sinkers, and all three walks and the lone hit by pitch were on a sinker. Clearly, he has limited control of the pitch.

However, there is still hope for the sinker. This year, as a secondary pitch against lefties, he’s been able to throw it more effectively for strikes and hold hitters to a .112 average against it. Maybe, if he were to use his fourseam as a main weapon against righties his sinker could be more effective in certain situations.

However, the credit to the increased success of his hard stuff could go to his new change-up, at least against lefties.

For the first time in his career, Nelson is throwing a tangible change-up. He’d never thrown a change more than 3 percent of the time, and the only time he even hit 3 percent was in 2014 where 3 of the 91 pitches he threw to lefties were change-ups.
This April, Nelson has thrown 28 change-ups (25 to lefties) which is 5.4 percent of his total pitches and only ten less than the 38 he threw all last year. So far, the change-up had been effective holding hitters to a .167 average and clearly, at least at this point, he’s committed to changing things up on the competition.

Nelson discussed his addition of the change-up, which he identified as having a split grip, in an interview with‘s Adam McCalvy this march. “I like this pitch,” he said. I like “the action it has on it.”

This is a pitch he’s been trying to establish as a secondary pitch since at least 2015 if not before. Tom Haudricourt of the Journal Sentinel mentioned his sporadic usage of a rare change in 2014 season in an article on March 6th, 2015.

The change is something that Nelson could implement further against righties. Currently, no-one has made contact against the three he’s thrown and it could possibly take attention of his fastball, sinker combination to make them more effective.

All of the changes Nelson chose to work on make sense, including his goal to become more physical fit and develop a strong base, and they seem to have been effective in helping him maintain his velocity while also reigning in his control issue. It makes me think he’s headed in the right direction.

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