The Clayton Kershaw Postseason Narrative Is a Myth

Clayton Kershaw threw seven pitches and recorded two outs in the Dodgers' Game 5 win over the Nationals.

They were seven big pitches and two crucial outs, but they were still just seven pitches and just two outs. And now people are acting like he’s some playoff superhero who rewrote his postseason legacy.

It's wrong. It's all so wrong. Not because it’s foolish to make grand declarations based off 2/3 of an inning -- which is true -- but because Kershaw hasn't actually struggled in the postseason. In fact, when he takes the mound in October, the game’s best pitcher has been pretty much the same, dominant ace he’s always been.

Narratives are the worst. Narratives are why people think Tony Romo is bad in the clutch (he's not) and that Tom Brady plays better when he's mad (he doesn't).

Narratives are the byproduct of lazy analysis, and they sometimes completely ignore what the data actually tells us.

When it comes to Kershaw, there are some numbers which point to him being a bad postseason performer; they're just not numbers we should use to evaluate pitchers. When we look at the advanced metrics, the message is clear -- it’s time for this “Clayton Kershaw is bad in the postseason” narrative to stop.

Mythbusters

But Kershaw is 3-6 with a 4.79 ERA in the playoffs while he is 126-60 with a 2.37 ERA in the regular season, you might say. That is true, but if you're using ERA and win-loss record to evaluate pitchers, you're probably using a dial-up connection to read this.

Simply put: there are better metrics out there which can more accurately tell us how a pitcher is truly performing by working to eliminate the things which are out of his control. When we look at Kershaw's advanced stats -- namely Skill-Interactive ERA (SIERA), strikeout rate, and walk rate -- things don't align with the narrative.

For those unfamiliar, SIERA is an advanced metric which estimates what a pitcher’s ERA should have been by heavily weighting the things a pitcher can most control. An emphasis is placed on getting strikeouts, limiting walks and inducing ground balls (since grounders result in extra-base hits less often than fly balls).

As you can see, the narrative is just flat out wrong. If we're making any argument, it should be that Kershaw is better in the postseason. The only area where playoff Kershaw hasn't topped regular season Kershaw is walk rate.

The Los Angeles Dodgers have made the postseason four straight years, and Kershaw has been ridiculously great each October.

Obviously, we're dealing with small sample sizes here, especially when looking at his postseason stats on a year-by-year basis, but there is no reason to think Kershaw is anything other than his usual freak show self in the playoffs.

So What’s Really Happening?

There is no denying it: Kershaw is giving up more runs per nine innings in the playoffs than he does in the regular season. That's why his playoff ERA is so much worse, and that's why the narrative lives on. But as the advanced metrics show, he is actually pitching just as great in the playoffs as he does in the regular season.

But if Kershaw is pitching so well, why are more runs crossing the plate? Well, he's giving up hits at the wrong time.

Kershaw’s strand rate -- the percentage of baserunners who end up stranded -- is significantly lower in the postseason. For his career, he owns a strand rate of 78.4%, but that number craters to 60.4% in the playoffs.

That doesn't tell us he isn't a good pitcher with runners on base; we have 1,760 innings worth of data which says otherwise. What it tells us is he's been unlucky in terms of timing, giving up costly hits with runners in scoring position.

The league average strand rate is around 70% to 72%, per FanGraphs, and a pitcher whose strand rate significantly deviates from the league average -- in either direction -- tends to see his strand rate regress to a league-average level over time. High-strikeout pitchers, like Kershaw, have shown some ability to maintain higher strand rates because their ability to get punch outs allows them to more easily work out of jams by limiting their exposure to the randomness of balls in play.

Despite Kershaw's high-strikeout ways, the dude has been done in by some bad timing.

Boring But True

Of course, attributing the postseason missteps of one of the all-time greats to randomness, bad luck and a small sample size isn't nearly as sexy as saying Kershaw is a choker and someone who can't perform under pressure.

But that's what makes sabermetrics and advanced stats so great. There is no narrative, no crap to sift through and no bias -- just data.

And the data clearly tells us that Clayton Kershaw doesn't mysteriously get worse when the calendar flips to October. He's still Clayton Kershaw, and he's still really darn good.

The narrative needs to disappear, just like his final pitch to Wilmer Difo.