The Postseason Pitching/Hitting Divide Might Be Widening

Ah, the playoffs. The odor of fall within the air, the sight of towel waving and packed stadiums throughout the nation, and the infinite stream of pontification on social media. Are the Rays simply not constructed for the postseason on account of an absence of star energy? Have the Dodgers been playoff slouches as a result of they’re too depending on their stars? Do the Astros know one thing about how Martín Maldonado manages a pitching workers that we don’t? Do we all know extra about easy methods to handle a pitching workers than John Schneider? The listing goes on.

Particularly with the brand new alternatives to weigh in given the expanded playoff structure, it’s been more durable than ever to hone in on concepts price pondering, not to mention hypotheses which might be falsifiable. However the different day, a xweet from MLB Community researcher Jessica Model caught my eye:

Of the 145 pitchers with 50.0+ innings pitched within the playoffs, their common ERA adjustments by -0.32. Genuinely stunned it is to their favor too!

Anxious about outliers? Median additional cements this level, at -0.36.

44 of 145 go up, 100 go down, 1 stays the identical: Catfish Hunter. https://t.co/AcqKFqyJyA

— Jessica Model (@JessicaDBrand) October 9, 2023

Due to our helpful new postseason leaderboards, this was certainly an attention-grabbing assertion that I may check. I restricted my pattern to hurlers who not solely tossed no less than 50 frames within the playoffs, however who additionally managed 500 innings within the common season. There have been 142 pitchers who met these standards, they usually averaged an ERA three tenths of a run decrease within the playoffs. Per a paired-samples t-test, this outcome was statistically important.

Earlier than we assume that this implies pitchers have the sting within the playoffs, or that pitchers are higher at bearing down in huge moments, there are a number of caveats to deal with. First, particularly given latest traits, we’ve got to bear in mind how pitcher utilization adjustments within the postseason. Think about the next, the place RS signifies “common season” and PS signifies “postseason”:

Conveniently, there have been 61 pitchers who pitched within the postseason completely earlier than the Wild Card period started in 1995 and 61 who pitched within the postseason completely after. If limiting the variety of batters confronted is the driving power behind the postseason ERA enchancment, we’d count on that enchancment to be considerably extra pronounced for the reason that Wild Card period started. But, the playoff bump is definitely extra pronounced pre-Wild Card. In truth, FIP thinks there isn’t even any playoff bump in any respect post-Wild Card.

After eradicating outliers (adjustments in batters confronted per look of greater than 10), the distinction between playoff and regular-season leash explains just below 15% of the variation in playoff bump, however in the wrong way of what I had anticipated:

That is probably as a result of faster hooks are reserved for pitchers who aren’t performing. Sure, managers have shorter leashes within the playoffs today, however that forestalls pitchers from regressing to the imply after a giant inning; in consequence, it’s really diminished the playoff bump.

What established it within the first place, then? What if pitchers are usually showing within the playoffs throughout their primes, whereas their common season stats additionally embrace the dawns and twilights of their careers? Maybe, on account of developments in coaching which have served to extend careers, this distinction has not been as highly effective lately; together with the faster hooks, that might clarify the diminished bump within the Wild Card period.

To check this concept, I took separate weighted averages of every pitcher’s age (with an help from Stathead) for his or her postseason and common season careers, weighted by variety of innings pitched. I discovered no relationship between the playoff bump and the distinction between these averages; in different phrases, showing within the playoffs extra typically throughout their prime had no affect on if these pitchers carried out higher within the postseason or the common season:

Then again, I additionally discovered little distinction on common between playoff age and common season age. So, even when there are some age-related results that I’m lacking, they wouldn’t actually clarify the playoff bump for this pattern.

Again to the drafting board. Possibly this query is rather a lot less complicated than it appeared at first look. To find out if pitchers maintain some type of benefit over hitters within the playoffs, why not run the identical process on hitters? This may even rule out the chance that choice bias is enjoying a job right here — perhaps the pitchers in my pattern are higher within the playoffs as a result of they’re higher than the typical pitcher, they usually’ve caught round lengthy sufficient to satisfy my sampling standards in consequence.

So I compiled a dataset of the 192 hitters who made no less than 150 postseason journeys to the plate and 1,500 common season ones. These gamers averaged a 99 wRC+ within the playoffs in comparison with a 116 mark within the common season; it wasn’t simply choice bias in spite of everything.

What’s actually occurring right here? For one, whereas the faster hooks could also be robbing starters of the chance to expertise regression, these starters would most likely nonetheless be extra weak to giving up runs than succesful relievers even when the starters stayed in and that regression did arrive. Positive sufficient, for the reason that Wild Card period started and people succesful relievers and faster hooks arrived en masse, the divide between postseason and common season wRC+ has been 19 factors (97 to 116); earlier than, it was merely 14 (106 to 120).

Moreover, although that is more durable to watch, workload constraints are usually loosened come October. Since pitchers are topic to those constraints extra so than hitters on account of their propensity for harm, the pitching facet stands to realize extra when these limits are lifted. This must be extra evident on the staff stage, as effectiveness per look would possibly go down with larger utilization however even a slightly-diminished elite reliever will decrease a staff’s ERA after they’re turned to extra typically. Alongside these strains, no less than anecdotally, pitchers appear much less afraid to max out with their velocity within the postseason. Whether or not that’s intentional or on account of adrenaline, it ought to serve to extend the pitching/hitting postseason divide as properly.

It may be powerful to sift by the noise of grand postseason theories, however there may be some fact to the maxim that the playoffs are a unique beast from the common season. It’s arduous to say how a lot the variations are a byproduct of tactical adjustments caused by suspicious managers versus the character of the event and the best way that gamers reply to it, however the pitching/hitting divide represents additional proof that we must always take the postseason/common season gulf severely regardless.