One of the favorite offseason pastimes of baseball fans and pundits is to speculate about negative regression; that is, the expected drop in production for various players. With the two best players on the 2017 Yankees - Luis Severino and Aaron Judge - coming off breakout seasons, it’s proven popular for people to speculate about their 2018 campaigns. Many believe the two young superstars are due for a dip in performance.
Certain players, and more importantly certain patterns, are largely regression proof, though. If either Judge or Sevy relied on luck or results-based approaches to hitting and pitching, they’d be prime candidates to drop off a bit in 2018. Instead, they count on positive processes to produce, and that kind of approach is what makes them such great candidates to repeat their success next season.
Let’s start with Aaron Judge. For all his prodigious power, Judge’s best asset is his eye. Leading baseball in walks while setting the all time rookie record for base on balls, Judge finished third in all of baseball in OBP. He finished behind only Joey Votto and Mike Trout, arguably the two best bats of this generation and certainly the most patient. Even in Judge’s well-publicized slump in August, he reached base at a .353 clip, 30 basis points better than league average.
This is important as on-base percentage, walk rates and other hallmarks of patient hitting are usually pretty sustainable year-over-year. We’ve seen other powerful hitters sustain their output by continuing to reach base as they age, with Nelson Cruz and David Ortiz being the best examples. Matching 80 grade patience with Judge’s natural power and the parks that make up the AL East mean he’s probably safe to remain one of the most terrifying hitters in baseball next season.
Moving on to Severino, we see that his case for continued success is even stronger. The young Dominican finished in the top 20% of baseball in K/9, BB/9, HR/9 and xFIP. Again, these show a process for Severino’s approach to batters that’s probably pretty sustainable. Severino relies on his velocity - a league best 97.6 mph on the fastball - and his slider and developing changeup to keep hitters off balance, and force a well-above average number of whiffs. Such a low walk rate indicates Sevy’s ability to stay in the strike zone, which is the most important factor for pitchers, and a perfectly healthy HR/9 rate shows that even when hitters make contact, it’s not high or hard enough to do significant damage.
xFIP essentially tries to measure what a pitcher’s FIP should be, based on strikeouts, walks and home runs, while discounting defensive or park anomalies. Severino ranks fourth in baseball, behind only Clayton Kershaw, Chris Sale and Corey Kluber in expected FIP. Like the above hitter’s examples, xFIP tends to be fairly stable across a career, giving more credence to the idea that 2017’s Luis Severino is here to stay.
Good arguments can be made that both Judge and Severino will improve in 2018. For Judge, cutting down on his high strikeout rate would make him even better, and Severino’s developing changeup should allow him to take advantage of the increased acceptance of strikeouts across baseball. I’m not going to get greedy, though, as the two stars combined for 13.9 fWAR last season, and I’d be happy with seeing that again. Even better, I think it’s likely we DO see it again.