Following up on our discussion of what happened to the Astros in their ALCS matchup with the 2018 World Champion Boston Red Sox, we thought it might be worthwhile to see if playoff teams--and World Series winners in particular--showed a pattern of hitting well against relief pitchers. (You should know that the Dodgers, the first losers in two consecutive World Series since the Rangers did in 2010-11, had their bullpen shredded by both of the teams that beat them--the Astros in 2017, and the Red Sox this year...the Dodger relievers posted a 5.48 ERA in the just-completed Fall Classic.)
Thinking more globally, we went back to the data at Forman et fils (baseball-reference.com) to look at the overall performance vs. relievers over the past decade. (That gives us nine years of data to work with--a total of 270 data points--just shy of what's needed to win twelve slightly used Dodger Blue™ cupcakes.) Do teams that make the playoffs hit better than average against relievers? And do teams that win the World Series exceed the average of "garden variety" post-season teams?
The answer to both these questions is "yes." The table at right breaks it all out for you. Teams that
made the post season have their OPS+ vs. relievers displayed in bold type. Teams with a 120 "sOPS+" (Sean's acronym, not ours!) are shown in scalding orange; we've also color-coded teams with 110-119 (pale orange), 100-109 (yellow), and--on the opposite side of the spectrum--teams whose "sOPS+" is less than 85 (pale, pale blue).
At the bottom of the chart you have some averages--these are yearly "sOPS+" averages for the playoff teams. As you can see, the figures are uniformly above league average: for the nine years in question, the average "sOPS+" is 107.
Finally, note the cells with the double-thick lines around them. These are the World Series winners. And, yes, the World Series winners (as seen in the double-thick-lined box at the very bottom right of the table) are better yet on average than their post-season also-rans. Over the past nine years, World Series winners have an aggregate "sOPS+" of 112 vs. relievers.
Now, doing well in this statistic doesn't guarantee you a trip to the post-season; after all, it's only one component of team performance. There are many examples of teams doing well in this statistic who didn't make it to the playoffs at all. But if you do make it, having an offense that is able to do damage against the opposition's bullpen seems to give you a measurable advantage with respect to winning the World Series.
(And to complete another historical tidbit that was given a teaser above: teams that lost consecutive appearances in the World Series include not only the 2017-18 Dodgers and 2010-11 Rangers, but the 1991-92 Braves, the 1977-78 Dodgers, the 1963-64 Yankees, the 1952-53 Dodgers, the 1936-37 Giants, the 1923-24 Giants, the 1921-22 Yankees, and two teams--the 1911-12 Giants and the 1907-09 Detroit Tigers, who are the only teams to lose three World Series in a row. By doing it this year and last, however, the Dodgers have joined the Giants as the only teams to have three instances of "two-time loser" syndrome in the World Series. To match their Bay Area rivals, they'll need to make it back to the World Series next year--and hit the skids again...)