Fielding Independent Risers, 2019

Recently I was perusing Aaron Nola’s baseball reference page, as one does, and took stock of his 2019 performance in relation to that of his breakout 2018 campaign. While a doubtlessly strong season, 2019 represented something of a clear backslide for Nola. 2018, very simply, was an incredible year for the right-hander, to the point that some level of regression might have been reasonably anticipated.

But an interesting aspect of Nola’s summary stats, to me at least, is the growth in all three of his three true outcome stats. Between 2018 and 2019, Nola walked more batters, allowed more home runs, and struck out more as well. He faced 21 more batters in 2019 (despite throwing 10 fewer innings) than he did in 2018, but he walked 22 more overall, allowed 10 more home runs, and struck out 5 more batters.

For hitters, adapting one’s game to the three true outcomes is a strategy that has increasingly payed dividends, hence the widespread trend in that direction. For pitchers, taking those three stats into account while quantifying performance helps isolate for the outcomes that individual can directly control. But how often is it that all three categories tick up from one year to the next?

To scratch the surface of this question, I have made use of FanGraphs’ Season Stat Grid tool to pick out starters who have reached 150+ innings in 2018 and followed that year up with a qualifying 162+ inning 2019. Of these pitchers, only players who had at least one three true outcomes statistic (given as K/9, etc.) rise year over year were considered. After filtering for these qualifications, just 28 unique pitchers remained. 

The following three charts are of pitcher seasons broken down by strikeout, walk, and finally home run growth season over season. 

Obviously, this is a chart any pitcher would like to find themselves on. Lucas Giolito is the runaway leader with a spike of more than 5 K’s per nine innings across seasons. All in all, just 21 pitchers made it on the list though. Furthermore, should 162+ innings have been a requirement for both 2018 and 2019, players like Rangers’ duo Mike Minor and Lance Lynn as well as Clayton Kershaw would have been filtered out based on their limited 2018 seasons.

Above is a leaderboard of a more ignominious nature. Still, walking batters for more than a few of these players didn’t ruin their value. The boards’ leader, Luis Castillo, in fact more than neutralized his walk rate by cutting down on home runs allowed and hiking up his strikeout rate in the same breath. Additionally, despite a jump of 1+ BB’s per 9, I don’t think any Nationals fan will be caught complaining about Patrick Corbin’s first year in D.C.

This final chart offers those pitchers whose home runs allowed per nine spiked in 2019.

Whether or not these players were especially stung by 2019’s infamous baseball is tough to tell. Players with 2018 home run rates as low as Trevor Bauer, Noah Syndergaard, and Jacob deGrom might have expected a bit of regression regardless in this era of home run dependence, but this list extends well past those three names. Justin Verlander, a vocal critic of 2019’s baseball, is another three true outcomes pitchers yet appears only in the bottom quartile of this chart.

To summarize, 21 pitchers made the strikeouts chart, 16 made the walks chart, and 20 appeared on the home runs list. 57 names altogether but, as aforementioned, just 28 unique individuals. To more visually break down how and where those players appeared, below is a Venn diagram to sort them out.

The diagram above does a better job depicting the tradeoffs various pitchers made in 2019. While all pitchers would most prefer to only have bumped their strikeout rates, it appears that pitchers who allowed more home runs while also striking out more batters fared well enough, given the types of seasons we saw from that group. Verlander, interestingly, took home the Cy Young award despite having taken steps back season over season in both BB/9 and HR/9.

Of course, the diagram above does nothing to highlight the magnitude that any given statistic rose in 2019. For instance, the Mets duo of Syndergaard and deGrom find their way into the center of the diagram only due to walk rates that inflated just barely. Regardless, the fact that the center features just 6 pitchers is fairly remarkable in and of itself. That center group increasingly took their starts into their own hands in 2019, but one wonders how they will aim to adapt from here.