Little has gone right for the Milwaukee Brewers this season, but it’s safe to say one of the bright spots has been the development of starting pitcher Jimmy Nelson. Formerly ranked as the team’s number one prospect and a top 100 prospect in all of baseball, Nelson received his first extended major league action in 2014 and at first glance was quite underwhelming: a 2-9 record in 14 games (12 starts), with a 4.93 ERA and 1.46 WHIP across 69.1 innings pitched. Jimmy’s peripherals were much better, however, and he showed the team enough to warrant trading longtime starter Yovani Gallardo in the offseason in order to open up a permanent spot in the starting rotation.
Many were wary of inserting Nelson into the rotation this season due to the fact that he was essentially a two-pitch starter last season at the big league level. This was mostly true, to an extent – Nelson actually throws two distinct fastballs, a sinker and a four-seamer – but the point is that Nelson combined to throw his fastball/sinker and slider for more than 97% of his offerings in 2014.
This year has been a different story, however. Nelson introduced a curveball into his repetoire during Spring Training and has successfully incorporated the pitch during the season, throwing it a little over 20% of the time, according to Brooks Baseball. Nelson’s full arsenal of pitches now offers three distinct velocities and types of movement to disrupt a hitter’s timing. While Nelson’s curveball has helped him become a legitimate starter this season, though, it’s his improved slider that has been his most dominant pitch.
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Nelson threw his slider about 25% of the time in 2014, and it was valued at 2.0 runs below league average according to Pitch F/X. This year with his new curveball, Nelson has had to rely on his slider less, throwing it only 17.7% of time. The results have been extraordinary, as Nelson’s slider is rated at 10.4 runs above average and is rated as the 15th best in the major leagues.
Jimmy’s slider velocity remained largely the same (with a slight uptick), averaging 87.91 MPH this season, but the movement is different than what we saw last season. Nelson has added about a half inch of horizontal break on the pitch, now at 4.64 inches according to Pitch F/X. He has also reduced the vertical movement from 0.91 inches to just 0.04 inches, giving the pitch more of a “boomerang” type break as it comes at the batter and breaking away from a right handed hitter.
Nelson has dominated right handed hitters to the tune of a .195 batting average and .556 OPS against, and the slider has been the biggest reason for his success. He has thrown about 79% of his 453 sliders to righties this season, who are batting just .081 with a .012 ISO against it. A right handed hitter has yet to slug a home run off Nelson’s slider this season. Nelson has been locating the pitch almost impeccably all season long, burying the pitch low and away to his glove side.
Jimmy Nelson’s slider heat map against right handed hitters in 2015, courtesy of Brooks Baseball.
The slider has by far been Nelson’s best strikeout pitch. Of his 147 strikeouts this year, Nelson has generated 50 of them off his slider. Jimmy throws his slider 40% of the time he is ahead of righties and 35% of the time he has two strikes on them. His slider usage takes somewhat of a back seat to his curveball against lefties, but he still uses it as a two strike pitch 23% of the time to southpaws. Hitters have swung at Nelson’s slider 53.2% of the time this season, more than any of his other pitches, and he’s induced an outstanding 39% whiff per swing rate on the pitch (for some context, Chris Archer of the Rays, who owns the game’s top rated slider this season, has generated a 36.52% whiff per swing rate). When batters do put the ball in play, they hit it on the ground nearly 48% of time.
Nelson has helped keep his slider effective by varying his usage throughout the season so that hitters can’t get a book on him. He has thrown as many as 33 sliders in a 103 pitch start against Arizona on May 29th, and as few as one in an 84 pitch outing against St. Louis on June 3rd. Hitters now not only need to keep in mind the slider in an offspeed count, but also be wary of a curveball that’s averages nearly five MPH slower with a totally different break.
All in all this season, Jimmy Nelson has pitched to a 3.95 ERA in 175.1 innings pitched with 147 strikeouts, 65 walks, and a 1.27 WHIP. Jimmy’s Deserved Run Average of 3.82 says he’s been even better than that, rating his individual performance at 11% better than league average. According to WARP, Nelson is ranked ahead of Taylor Jungmann as the best among Brewers’ pitchers, and and at 2.52 wins above replacement player he is rated as the 36th most valuable pitcher in baseball. Thanks in large part to his wipe-out slider, Jimmy Nelson has carved himself out a role near the top of the Milwaukee Brewers starting rotation for the foreseeable future.