The Constantly Evolving Jimmy Nelson

My intrigue with Jimmy Nelson began over two years ago, when I first saw him pitch in Triple-A. Since then, the now-26-year-old has only gotten more interesting, as he’s made several significant adjustments in his quest to stick as a quality major-league starter. Back in May 2014, Nelson’s repertoire focused on the combination of his mid-90’s four-seam fastball and mid-80’s slider, with work-in-progress versions of a sinker and changeup. His delivery — especially his release point — was far from consistent, causing his command to be an irregular guest.

Of course, ironing out problems like this is what the term ‘player development’ is all about. In David Laurila’s interview with Nelson from last August, Nelson discusses smoothing out his delivery:

“It was a mechanical change. Instead of going over my head with my hands to start my delivery, now I just keep them in front and drop them down. That allows me to be more consistent and repeatable, and a lot more relaxed.”

Nelson’s repertoire and pitch usage saw even more adjustments over the last couple years than his mechanics. By the time he got the call to the majors in mid-July 2014, he was throwing more sinkers than four-seamers, a trend that continues to this day. Through his first 308 major-league innings, he’s throwing his sinker at a 40.4% rate, compared to 25.1% for the four-seamer.

An even more significant alteration to his arsenal was the addition of two spike curveballs in 2015 — one of the mid-80’s variety, as well as a low-80’s version with deeper vertical break. Instead of the pitcher he was in the minors — a two-pitch guy struggling to find his third — Nelson now throws six pitches.

On the surface, there’s plenty not to like about Nelson’s first eight starts of 2016. While the righty possesses a 3.51 ERA and 1.17 WHIP, there’s more than a couple red flags in his data thus far. On average, he’s served up one homer in each start (eight in 51.1 IP), after allowing 18 in his 30 starts (177.1 IP) last year. His swinging-strike rate is just 6.8%, compared to last year’s 10%. Both his career-low .234 BABIP and career-high 74.8% strand rate seem due for correction.

However, Nelson is also doing some rather eye-opening things on the mound, in a good way. First off, that .234 BABIP is at least partially due to the fact that he’s generating a ton of weak contact. His 24.8% soft-hit rate is good for ninth-best among all major-league starters, and he’s also got the 15th-lowest line-drive rate (15.9%). His 16% HR/FB rate will almost certainly drop at some point, and if some of that weak contact turns into missed bats, it’s easy to see Nelson experiencing a modest breakout.

As Paul Sporer pointed out in his preseason player capsule on Nelson, the right-hander’s most glaring issue in 2015 was his ineffectiveness against lefty hitters. This year is a vastly different story thus far, as he’s suppressed lefties down to a much more reasonable level:

  • 2015 vs L (334 PA): .298/.381/.495, .376 wOBA
  • 2015 vs R (418 PA): .198/.275/.293, .255 wOBA
  • 2016 vs L (92 PA): .205/.286/.407, .302 wOBA
  • 2016 vs R (119 PA): .224/.308/.365, .299 wOBA

While righties are doing a bit more damage than last year, his improvement against left-handers is more than making up for it to this point. When examining his data, it’s not difficult to identify the ways in which Nelson changed his approach when facing lefties this season. He’s relying far more on his hard stuff, with a full 76.4% of his pitches to left-handers consisting of fastballs and sinkers — a major increase from the 58.9% rate at which he threw those pitches to lefties last year.


You can see the massive drop in his curveball usage, and he’s throwing about 40% fewer sliders as well. When he does throw the curve to lefties, he’s throwing the slow version more often than he did last year, likely as an alternative to his painfully ineffective changeup.

Nelson also changed the way he throws his four-seamer to lefties. In 2015, he threw lefties a ton of heaters in the middle third, from the belt up. Believe it or not, this was an ineffective strategy.


This year, he’s going upstairs with the heater even more often, but now he’s pounding the ball inside instead of leaving it over the middle of the plate:


As a result of this adjustment, left-handers are hitting a paltry .138/.167/.241 against Nelson’s four-seamer, as opposed to last year’s .218/.283/.473. The fastball also seems to be setting up his breaking balls for greater success, as lefties remain hitless against Nelson’s curveball and slider through his eight starts.

When you examine all of these factors together, you start to understand how completely Nelson changed his strategy to limit lefty hitters’ effectiveness. Last year, he attacked lefties down in the zone, using primarily his sinker and his hard curve. On the few occasions that he did throw them something above the waist, he frequently put the ball in the middle third of the plate.

This year, he’s still throwing his sinker mostly down and away — and at an even higher rate than last season — but he now also comes up and in with the four-seamer, and is transitioning from the hard curve to the softer one. In doing these things, Nelson is forcing left-handers to change their eye level with greater frequency, and although he’s narrowed down his arsenal against lefties from roughly five pitches to three, the turn to the softer curve also expands the range of pitch speeds a batter needs to look for.

This is what I like about Jimmy Nelson. From developing two curveballs last year, to completely changing his strategy against lefties this season, he’s constantly searching for ways to become a more effective pitcher. He’ll probably never be a true ace, but with his 6’6″, 245 lb frame and a fastball that dials up to the 96-97 mph range when he needs it, he’s a relatively high-floor commodity.

As he’s shown through his ability to successfully adapt his craft at the game’s highest level, Nelson’s ceiling might be a bit higher than we thought it was too.

Scott Strandberg started writing for Rotographs in 2013. He works in small business consultation, and he also writes A&E columns for The Norman Transcript newspaper. Scott lives in Seattle, WA.

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Dewey Ever
Dewey Ever

Thanks for the article. I think what I don’t get is the vastly better results at home than on the road the last 2 years. From the fantasy baseball standpoint, it makes it easier to know when to start him. But it’s baffling especially when you consider which is his home park.