Clayton Kershaw had the best postseason start of his career

Narratives can be the worst. Sometimes, a narrative can be grounded in a truth, but, at least in sports, it feels as if there is often more to the story. The “Clayton Kershaw can’t handle the postseason” narrative is probably one of my least favorite claims. Kershaw has arguably been the best pitcher of this era, yet his greatness is seemingly always criticized with this so-called “inability” to perform under pressure.

The thing is: Kershaw’s October numbers do look... underwhelming. But, even then, there’s so much more. He’s been dealt some incredibly tough hands, been asked to pitch on short rest, and has had relief appearances between starts that have made him less effective his next time on the bump. Not to mention, the Dodgers’ bullpen has had an odd knack for allowing what seems to be a ton of runners he leaves on base to ultimately score, further inflating Kershaw’s postseason ERA.

This might sound like a series of excuses in defense of Kershaw, but it indicates the crux of the issue: sample size. Even for a pitcher with as many postseason starts as Kershaw, the playoff-induced randomness has yielded a half-run gap between his playoff ERA and his playoff FIP in 33 appearances. Over no 33-game stretch during Kershaw’s entire regular season career has he posted an ERA this far above his FIP. In fact, Kershaw hasn’t had a 33-game stretch with an ERA above his FIP at all since 2016:

That’s why some of this can be chalked up to luck, but on Tuesday, things seemed different, hopefully for more than just a moment. Kershaw turned in a vintage regular season Clayton Kershaw start. In a potential series-clinching Game 2, Kershaw completely shut down the Brewers, pitching eight scoreless innings with a baker’s dozen strikeouts. In his masterful outing, Kershaw induced 24 swings-and-misses, a season-high, and posted a 44.1 percent called-strike-plus-whiff rate, the sixth-highest rate of any start of at least 80 pitches this season. Behind the gem, the Dodgers advanced to the National League Division Series with the 3-0 victory.

By game score, the start was the best postseason outing of Kershaw’s career, which is quite the declaration considering he’s made 26 career postseason starts spanning 11 years:

Kershaw’s dominance shouldn’t really come as a surprise, especially with his increased fastball velocity ticking up his 2020 regular season performance. However, it was still a welcome sight for those who have argued, demanded, pleaded that Kershaw’s postseason woes have come more as a result of poor luck than any noticeable dip in performance.

Though he had never pitched as well as he did on Thursday, Kershaw has been good in the postseason in the past, and perhaps some of his misfortune in prior Octobers has been the result of mismanagement and thin bullpens. As Jon Weisman points out, Thursday represented Kershaw’s 12th postseason start allowing two or fewer earned runs. It was also his 17th career postseason start allowing two or fewer earned runs in the first six innings.

Additionally, among active starters, Kershaw is tied for the second-most postseason starts with 10 or more strikeouts and two or fewer walks. These sort of pitching performances sound quite dominant, and the data supports the inclination: In 2020, in outings with at least 10 strikeouts and no more than two walks, pitchers posted a 1.60 ERA. And when compared to results from fellow postseason starters, Kershaw’s results in these games stick out like a sore thumb:

You can certainly nitpick some of this, sure. Kershaw has a career 26 postseason starts, so it’s far less impressive that he has four outings that fit this criteria than, say, Gerrit Cole, who has 11 carer postseason starts, or Stephen Strasburg, who has just eight. The point, however, is less about the percent of the time Kershaw puts up a stat line like this, but more about how, even when he does, he has trouble escaping his poor postseason luck. Consider it this way: Kershaw has allowed three more earned runs in his four postseason starts with 10 or more strikeouts and two or fewer walks than the other four pitchers listed here have allowed combined.

Or, you could think this way: If you assume that Kershaw even pitched to a 2.00 ERA during these four starts — which, notably, would still be the worst mark of the group — his postseason ERA drops by more than four-tenths of a run, from 4.22 to 3.79. The fact that “Kershaw has a postseason ERA over 4.00” would be no more, and his results would begin to look more similar to those of Max Scherzer (3.38 postseason ERA) and Justin Verlander (3.40 postseason ERA).

Really, this is just another lesson in postseason randomness, and is something that can be seen using more conventional methods as well. Kershaw has a 2.43 regular season ERA and a 4.22 postseason ERA, despite nearly identical strikeout and walk rates in the regular season versus the postseason. His 3.71 postseason FIP is inflated because of his uncharacteristically-high 14.8 percent HR/FB rate — adjust for this, and his expected FIPs become relatively close, a 74 xFIP- in the regular season to an 82 xFIP- in the postseason.

The problem is, though, none of this matters unless Kershaw can produce. Over a normal-length 162-game season, starts with a ton of runs allowed might not matter: Kershaw can be excused for having an unlucky day, especially when the numbers under the hood still look good. But in the playoffs, unlucky days can’t become the norm. That’s just the nature of pitching when the season is on the line. And on Thursday, Kershaw came through. Let’s hope that there is more of that over the rest of these playoffs.

Devan Fink is a sophomore at Dartmouth College and a Contributor at Beyond The Box Score. Previous work of his can be found at FanGraphs and his own personal blog, Cover Those Bases. You can follow him on Twitter @DevanFink.