Sometimes, success is objective - the Nationals won the World Series, the goal of most of the teams in MLB, so nobody could argue they had an unsuccessful season. Sometimes, success is subjective, like Mike Trout’s entire career. He’s maybe the most talented player we’ve seen in a century, but he’s had trouble with wonky injuries and a lack of postseason appearances. I’d call him a success story, but some people might argue that.
Success is also often relative - past seasons would have seen a 30 home run hitter be considered one of the best power hitters in the game, but in 2019, 57 players hit at least 30 dingers, significantly altering our definition of power hitters. As the average or replacement level of talent changes, so do our ideas of success.
Oftentimes, the higher the expectations, the more subjective success becomes. Gerrit Cole comes to the Bronx with sky-high expectations, and it’s fair to ask what we would consider a good, or even great, season from the Yankees’ new ace. In 2019, Cole led all of baseball in K-BB rate, fWAR, and xFIP, while finishing second in FIP and third in ERA. It’s pretty hard to pitch any better than that, and if you just copy and paste his 2019 results, we’d all say that was what we want out of him.
How much regression can still be considered “success”, though? Steamer projects Cole to be the best or second-best pitcher in baseball again, despite having not quite as good a year in 2020. He’s pegged for a 30% increase in ERA, a 19% increase in FIP and a 19% decrease in K-BB rate. Projection systems are always conservative, and all of his metrics still look terrific despite some regression. If every player in baseball matched their projections, Cole is still a Cy Young finalist, and I think we’d call that a success.
Just for fun, let’s regress that ERA and K-BB% another 10 points. A 40% regression in ERA gives us a 3.50 mark, and a 30% (I’m rounding, leave me alone) regression in K-BB% is 23.8%. Is that successful? Like we said above, that’s probably relative to how the league performs.
Here’s that regressed Gerrit Cole, plotted against the performance of the rest of baseball in 2019. He’s still well above average, but instead of the best pitcher in baseball, he’s somewhere between Lucas Giolito and Jake Odorizzi - good but not the elite tier of baseball. I suspect this would not be seen as a successful season, given the expectations at the start of the season.
Success can be objective, subjective, and relative all at once. If Cole is a unanimous Cy Young winner, but loses twice in an ALDS that the Yankees drop to Oakland or something like that, people probably aren’t going to see that as a successful season. Statistically at least, it’s hard to envision a situation where we’re not happy with Cole’s 2020, but stats aren’t always the biggest driver of perception.