October Trends: How the 2020 Postseason Stacks Up

The ALCS between the Rays and Astros and the NLCS between the Dodgers and Braves have both produced tight, dramatic contests thus far, full of home runs and low scoring. As such, it’s a good time to check in on some of the trends that defined the brief 2020 season, and how they compare to what we’ve seen in the postseason, and how this October compares to recent regular and postseasons.

For starters, well, there are the starters. As I noted just two weeks into the abbreviated regular season, the length of the average start had fallen below five innings, and while it rose slightly over the remainder of the 2020 campaign, it still finished below five. Updating the table I included with that piece:

Starting Pitcher Regular Season Performance 2015-20
Season IP/GS Change K% BB% HR/9 ERA ERA- FIP FIP-
2015 5.81 -2.6% 19.5% 7.1% 1.06 4.10 103 4.03 102
2016 5.65 -2.8% 20.2% 7.7% 1.24 4.34 104 4.3 103
2017 5.51 -2.4% 20.6% 8.1% 1.34 4.49 103 4.48 103
2018 5.36 -2.8% 21.6% 8.0% 1.21 4.19 101 4.21 101
2019 5.18 -3.4% 22.3% 7.7% 1.44 4.54 101 4.51 100
2020 4.78 -7.7% 22.9% 8.3% 1.30 4.46 100 4.46 100

The year-to-year drop in innings per start was the largest we’ve seen in this span, and indeed the largest we’ve seen in the Wild Card era, if not longer. Granted, it was a short season, with a short ramp-up, expanded rosters, as well as a ton of seven-inning doubleheaders, something we’ve never seen at the major league level before, but that wasn’t really factor when I checked in on the first two weeks; I used data through August 5, at which point only one seven-inning doubleheader had been played.

Anyway, through this year’s Wild Card and Division Series, starting pitcher workloads decreased even further:

Starters have averaged fewer than five innings per turn in three of the past four postseasons; with the likes of Gerrit Cole, Stephen Strasburg, and Justin Verlander frequently pitching deep into games — six or more innings a total of 14 times between them — last year was the exception. While the average through the first two rounds fell to its lowest level this year, the drop-off relative to the regular season is about on par with the period in question:

Regular vs. Postseason Start Length
Year Reg IP/GS Post IP/GS Dif
2015 5.81 5.51 -5.2%
2016 5.65 5.11 -9.6%
2017 5.51 4.73 -14.1%
2018 5.36 4.68 -12.7%
2019 5.18 5.14 -0.9%
2020 4.78 4.37 -8.5%
Avg 5.45 4.93 -9.5%
2020 data includes only Wild Card Series and Division Series.

The particularly short starts from this postseason, I believe, reflect both the urgency of the short series — including the unprecedented best-of-three round (ugh) — as well as the increased use of openers and bullpen starts. On that subject:

Postseason Start Length
Year GS ≤ 3 IP % ≥ 6IP %
2015 72 9 12.5% 36 50.0%
2016 70 7 10.0% 24 34.3%
2017 76 15 19.7% 25 32.9%
2018 66 15 22.7% 19 28.8%
2019 74 10 13.5% 33 44.6%
2020 66 16 24.2% 18 27.3%
SOURCE: Baseball-Reference
2020 data includes only Wild Card Series and Division Series.

Nearly one-quarter of the starts from the first two rounds lasted three innings or less. Admittedly, that’s lumping together some quick hooks of ineffective starters (Hyun Jin Ryu, Chris Paddack, Zach Davies, and Carlos Carrasco, for example) with bona fide openers (Deivi García, Dustin May, Ryan Thompson) who were followed by primary pitchers, and also bullpen game starters (including, inadvertently, Mike Clevinger). While it may be something of an apples to oranges comparison with any year before 2018, the year that the opener came into vogue, this year’s best-of-three round has created its own type of fruit salad anyway.

Where starts of at least six innings were three to four times as common as such short starts in 2015, ’16, and even ’19, the rates of those types have been converging, last year aside; those “long” starts have become about half as common as they were just five postseasons ago. Meanwhile, for the first time in this span, starts of two innings or fewer outnumbered those of seven innings or more, 11 to seven, a count that does not include Lance McCullers Jr. going seven in Monday’s ALCS Game 2 (the three LCS games have boosted the average to 4.48 innings per start, in case you’re wondering).

We haven’t even discussed actual pitcher performance, but as you might expect from the lower innings per start, postseason starters aren’t doing great:

Starter/Reliever Postseason Comparison
2015 4.33 4.17 108 108 3.55 3.40 88 88
2016 3.88 3.86 113 109 2.88 3.16 84 89
2017 4.08 4.32 101 101 3.97 4.20 99 98
2018 3.90 3.96 104 103 3.60 3.75 96 97
2019 3.36 3.91 90 97 4.24 4.23 113 105
2020 4.52 4.55 110 106 3.74 4.02 91 94
FIP uses regular season constants and thus does not reconcile. ERA- and FIP- do not include park adjustments.

A couple of caveats are necessary here. First, I’m using the regular season FIP constants, which are calculated so that a league’s ERA and FIP reconcile for that season, but that isn’t the case within the limited samples of games here. The ERAs have generally been lower than the FIPs, which is because scoring is lower in the postseason relative to the regular season, a fact you probably knew already; this year, teams scored 4.65 runs per game during the regular season, and 4.44 during the first two rounds (more on that subject shortly). Second, for the ERA- and FIP- metrics, I’m not using any park factors; these are just the split ERAs (or FIPs) relative to the overall league ERAs (or FIPs).

Still, what stands out is that last year was a significant aberration in that starters far outperformed relievers. Every other year within this span, it’s the other way around, and thus far this year, the gap has been wider than any year since 2016.

Turning to the offenses, first it’s worth noting that the scoring drop-off we saw through the first two rounds was actually less than usual, even with the stifling performances of the Braves, who entered the NLCS having allowed five runs in five games, and the Dodgers, who likewise allowed just 11 runs over the same stretch:

Regular vs. Postseason Scoring Levels
Year Reg R/G Post R/G Dif
2015 4.25 4.36 2.6%
2016 4.48 3.70 -17.4%
2017 4.65 4.29 -7.8%
2018 4.45 4.00 -10.1%
2019 4.83 4.03 -16.6%
2020 4.65 4.44 -4.5%
Avg 4.54 4.14 -8.9%
2020 data includes only Wild Card Series and Division Series.

If we include the games to date from the ALCS and NLCS, this year’s level drops to 4.28 runs, a dip of 8.0%, but it should be noted that the participating teams have had the chance to line up their rotations to put some of their top starters out there thus far, and we shouldn’t expect those series to continue producing just 2.5 runs per team per game.

As for homers, after record levels during the 2019 regular season, we saw something of a drop-off this year, but it was still the second most homer-happy season in history. Lo and behold, even more balls flew over the fences in the first two rounds, that despite the shift to the cavernous neutral zone of Globe Life Field for the Dodgers-Padres series, which — gasp — featured just three homers in three games:

Regular vs. Postseason Home Run Rates
Year Reg HR/G Post HR/G Change Reg HR/PA Post HR/PA Change
2015 1.01 1.26 25.1% 2.7% 3.4% 26.2%
2016 1.16 1.01 -12.2% 3.0% 2.7% -9.7%
2017 1.26 1.37 8.9% 3.3% 3.7% 11.7%
2018 1.15 1.08 -6.4% 3.0% 2.8% -8.4%
2019 1.39 1.28 -8.0% 3.6% 3.4% -6.3%
2020 1.28 1.41 9.8% 3.5% 3.7% 6.7%
Avg 1.20 1.24 3.2% 3.2% 3.3% 4.1%

Through the first two rounds, we saw a higher rate of home runs per game and per plate appearance than we’ve seen in any regular season — an increase of nearly 10% relative to this year’s regular season per-game rate, though a bump of just 6.7% if we go by plate appearances (note that I’m not referring to the percentage point gains here, which are much smaller). By either measure we’ve seen some rather drastic swings relative to regular season rates, sometimes positive, sometimes negative, and while most of it comes out in the wash, the reality is that we’re seeing more homers. The increase stands out more if we factor in the higher strikeout rates, which are a product of both better pitchers taking a greater share of innings, and relievers taking a greater share than usual:

Regular vs. Postseason Homer and Strikeout Rates
Year HR/Con HR/Con HR/Con Dif Reg K% Post K% K% Dif
2015 3.8% 5.1% 33.1% 20.4% 24.2% 18.7%
2016 4.4% 4.1% -5.6% 21.1% 24.4% 15.3%
2017 4.8% 5.7% 18.9% 21.6% 24.7% 14.3%
2018 4.5% 4.3% -2.7% 22.3% 24.7% 11.0%
2019 5.4% 5.4% -1.1% 23.0% 26.1% 13.9%
2020 5.3% 5.8% 9.7% 23.4% 25.1% 7.3%
Avg 4.7% 5.1% 8.8% 21.8% 24.9% 14.2%
HR/Con = HR/(AB – SO + SF)

Again, I’m working with percentage gains rather than percentage point gains in order to emphasize the relative increases and keep them on the scale of the previous table. Where by home runs per plate appearance this year’s first two rounds saw a 6.7% increase, it’s up to 9.8% if we factor in contact rates, because pitchers are missing more bats — though the extent of the increase there is less than it’s usually been.

Naturally, given what we’ve witnessed in recent years, this leads to speculation about whether the ball is juiced, or at least has different characteristic from what we saw in the regular season. On that subject, I’ll defer to Rob Arthur, who earlier this season observed that the 2020 baseball was less aerodynamic than last year’s ball and that its drag was inconsistent (which isn’t to say that 2020 hasn’t been a consistent drag in the grand scheme of things). Writing on October 9, he noted that while there hasn’t been any “playoff surprise” like last year, when it appeared that the postseason ball had been dejuiced, we’ve seen a more juiced ball this postseason, albeit via an as-yet-unexplained spike in exit velocity rather than drag.

That trend will certainly take more data to iron out, and indeed, likewise for the trends above. Thus far we’ve seen downturns in starting pitcher usage and overall scoring rates, but higher home run and strikeout rates. As a result, a greater share of the runs scored are coming via home run:

Regular vs. Postseason Percentage of Runs via Home Run
Year Reg R/HR% Post R/HR% Dif
2015 37.2% 41.7% 4.5%
2016 40.2% 42.5% 2.3%
2017 42.3% 50.9% 8.7%
2018 40.2% 42.4% 2.3%
2019 45.2% 46.6% 1.4%
2020 43.7% 50.2% 6.5%
Avg 41.3% 45.9% 4.6%
2020 data includes only Wild Card Series and Division Series.

Already in the two LCS we’ve seen 11 out of the 15 runs scored come via home run, so it’s possible this trend will set a record in that regard. And while it probably shouldn’t need to be said except as a corrective to some of the handwringing in the broadcast booths, teams that out-homer their opponents are now 24-1 including the two LCS. I strongly suspect that will remain the case through the two Championship Series and the World Series, though given the lack of off days in the LCS, we’re likely to see the innings per start rise, as it’s untenable for teams to overburden their top bullpen arms night after night. We’ll check back in on some of these trends as October continues.

Brooklyn-based Jay Jaffe is a senior writer for FanGraphs, the author of The Cooperstown Casebook (Thomas Dunne Books, 2017) and the creator of the JAWS (Jaffe WAR Score) metric for Hall of Fame analysis. He founded the Futility Infielder website (2001), was a columnist for Baseball Prospectus (2005-2012) and a contributing writer for Sports Illustrated (2012-2018). He has been a recurring guest on MLB Network and a member of the BBWAA since 2011. Follow him on Twitter @jay_jaffe.

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Cave Dameron
Cave Dameron

Half the runs scored by home run. Yuck