On October 15th, 2020, Clayton Kershaw’s night was off to a great start. Through five innings, he’d let just one Atlanta Brave cross the plate while striking out four. But while facing that same lineup the third time over, Kershaw allowed three straight hits to open the sixth inning and didn’t record an out. Those hits allowed the Braves to take a lead they’d never give back, and continued a long and bizarre trend of postseason impotence for one of the greatest pitchers of this generation.
Kershaw’s career playoff ERA is nearly two full runs higher than his career regular season mark of 2.43. We’re not exactly drawing from a small sample size anymore, either; he’s now pitched 177 ⅓ postseason innings, which is basically the equivalent of a full season. So what gives? Why is Clayton Kershaw bad in the playoffs, but stellar in the regular season? After some digging, I’ve figured out five factors that help to explain this wild anomaly, and I’ve listed them in ascending order from “eh, maybe I guess” to “yep, that’s gotta be it”.
5. Better Competition
This should be obvious, but it’s worth a place on this list anyway. Take any pitcher who’s been around long enough, and unless that pitcher is named Madison Bumgarner, odds are that they’ll have worse stats in the postseason than the regular season. By default, the teams who make the playoffs are the toughest teams to beat. So in October, your competition goes from all 30 teams to the top ten or so.
That doesn’t explain the extent of Kershaw’s postseason futility, which is far more pronounced than that of most former Cy Young Award-winners, of course. But it probably accounts for something. A cursory glance at some recent all-time greats (with large playoff sample sizes) shows that the postseason is just generally a tougher environment to consistently excel in on the same level… pitchers such as Roger Clemens, Randy Johnson, Pedro Martinez and C.C. Sabathia were all around half a run worse in the playoffs than the regular season on average.
So even if we can’t blame Kershaw’s October inefficacy on better competition alone, we can say that it probably makes the narrative look a bit worse than it really is.
Although Kershaw isn’t necessarily the workhorse he once was (he’s missed time in several recent years due to injuries), that left arm has a ton of innings on it. The human body simply isn’t built to make a maximum effort throw a hundred times in one night every five days, and that effort has a greater impact on some pitchers than others. It could be that Kershaw is just a little worn down by the time October comes around. It’s certainly worth bringing up that his career postseason stats are more troubling in the NLCS than they are in the NLDS, and they get even worse in the World Series.
3. Cheating Opponents
This is another factor that can’t entirely explain Kershaw’s playoff issues in and of itself, but when we look at all of these smaller factors at once, they begin to add up and form a more interesting picture. The Dodgers ace faced the Houston Astros twice during the 2017 World Series, and we now know that his opponent was illegally stealing signs on a massive scale, en route to an illegitimate title. Not only that, but he made two starts against the Red Sox in the following World Series, who were also stealing signs on a slightly smaller scale.
In the grand scheme of things, those starts account for only 15% of Kershaw’s total postseason innings. That means his stats across them (including a 5.40 ERA) don’t actually have an earth-shattering impact on his career postseason totals. There is, however, a crucial factor at play here: these are Kershaw’s only World Series appearances. If they’d been exceptional, or even just solid performances, the narrative surrounding Kershaw’s playoff struggles probably flips on its head. “Sure, he doesn’t have perfect postseason numbers overall, but he’s dominant in the World Series.”
If the Astros and Red Sox had been playing by the rules like everyone else, there’s a good chance that Kershaw’s World Series stats look just fine, and there’s an even better chance he walks away with a pair of rings to show for it. In that reality, people probably aren’t really discussing the Kershaw postseason narrative in the same way they are now.
2. Questionable Management
Whether it’s been Don Mattingly or Dave Roberts at the helm for Los Angeles, Kershaw has typically been asked to go deep into games during the postseason. That’s particularly true during a few of Mattingly’s years when the Dodgers had a weak bullpen beyond Kenley Jansen. Several of Kershaw’s October clunkers would actually look like average or even dominant performances if he’d only been pulled four or five batters sooner. To be honest, these managers should know by now that Kershaw isn’t as effective the third time through the order, and that’s on them.
And speaking of management, there’s the matter of time between starts to consider. The future hall-of-famer has been asked to take the ball on short rest ten times during his postseason career. That’s not uncommon in the playoffs, but the results generally aren’t good for these types of starts. According to the Washington Post, there were 121 total instances of a pitcher starting on three days’ rest in the playoffs between 1995 and 2016; those pitchers compiled a combined 35-40 record with an unsightly 4.35 ERA. Oddly enough, that figure is almost an exact match for Kershaw’s 4.31 career ERA in the postseason.
1. Bad Luck
I get it… this probably sounds like the lamest excuse in the book. Blaming nearly 180 innings’ worth of below-average pitching performances on bad luck would be a complete cop-out in most cases. But when it comes to Kershaw’s issues in October, there are some luck-based factors that are simply too eye-popping to ignore.
Let’s start by taking a look at a somewhat obscure state I like to follow. It’s called strand rate, although you’re more likely to see it written as LOB%. As that acronym indicates, strand rate is a measure of the percentage of opposing baserunners were Left On Base when the inning ended, as opposed to crossing the plate. More talented pitchers generally have a higher strand rate than average or mediocre ones, simply because they record outs at higher rates. But any extreme variation in a pitcher’s strand rate from year to year is largely considered by statisticians to be a matter of luck; that’s why true talent metrics like FIP and SIERA normalize it as part of their formula.
Kershaw’s regular season strand rate has hovered within a few points of 80% in every year of his career, even while his ERA has varied more greatly. But his career strand rate in the playoffs? That’d be a dismal 67.2%. That explains why he holds a more palatable 3.81 postseason FIP in comparison with his 4.31 ERA. Does the fact that Kershaw strands fewer baserunners in the playoffs say anything about his talent? Based on everything we know about baseball, the answer is a resounding “no”.
Strand rate is only half of the picture when it comes to luck, though. While this might come as a surprise to some, a pitcher’s homer-to-fly-ball ratio (HR/FB%) is widely considered to be a matter of luck. See, while a pitcher generally has some level of control over the type of contact they allow (ground balls, line drives, and fly balls), they have very little control over whether the fly balls they give up will ultimately stay in the park, or die in the glove of an outfielder. Kershaw’s career HR/FB% in the regular season is 9.2%, but in the playoffs he owns a mark of 15.4%.
Remember that 3.81 postseason FIP we talked about earlier? xFIP is a stat that measures a pitcher’s true talent in the same way, but also normalizes a pitcher’s HR/FB% to the typical league average (10%), and adjusts earned runs accordingly. Kershaw’s xFIP in the playoffs is 3.42… nearly a full run below his ERA.
If we take that 3.42 figure and bake in a half run to account for the toughness of playoff competition, the narrative looks much different. Then, if we offer some additional forgiveness for perceived mismanagement and consider how often he started on short rest or faced opponents who were cheating, suddenly there’s a better explanation for Kershaw being bad in the playoffs beyond the cliché “he’s just not clutch”.