Does Postseason Play Hamper Future Production?

There is no need to beat around the bush with an intro full of cliches and examples. Simply does playing in the postseason wear down a player enough to effect their next season’s production?

Simple answer: Not really.

Less simple answer: Some with hitters, not at all with pitchers.

Complex answer: Danger math.

To answer this question, I just compared four sets of data (2010 to 2018) for both pitchers and hitters. Here are the four datasets (same label at the tables).

  • Regular: Regular season stats for the season playing in the postseason.
  • Postseason: Postseason stats
  • Steamer: Steamer projections
  • Next Season: Stats from the next season.

For hitters, I used OPS since I’m able to convert changes in OPS to changes in roto categories. For pitchers, I used ERA. I found the average and median changes in each player’s stats. I prefer the median value since it helps to remove extreme values that can occur, especially with ERA. I’ll start examining the hitters. Here are average and median differences.

Median Change in OPS for Postseason Hitters
Postseason PA Postseason – Regular Steamer – Regular Next Season – Steamer Next Season – Regular
> 70 -.078 -.031 -.005 -.034
60 to 69 -.113 -.033 -.015 -.052
50 to 59 -.128 -.023 -.013 -.038
40 to 49 -.131 -.031 -.026 -.041
30 to 39 -.106 -.008 -.014 -.026
20 to 29 -.132 -.007 -.011 -.028
10 to 19 -.162 -.010 -.018 -.032
1 to 9 -.464 -.001 -.023 -.029
Overall -.184 -.011 -.017 -.033

 

Average Change in OPS for Postseason Hitters
Postseason PA Postseason – Regular Steamer – Regular Next Season – Steamer Next Season – Regular
> 70 -.078 -.031 -.005 -.034
60 to 69 -.113 -.033 -.015 -.052
50 to 59 -.128 -.023 -.013 -.038
40 to 49 -.131 -.031 -.026 -.041
30 to 39 -.106 -.008 -.014 -.026
20 to 29 -.132 -.007 -.011 -.028
10 to 19 -.162 -.010 -.018 -.032
1 to 9 -.464 -.001 -.023 -.029
Overall -.184 -.011 -.017 -.033

It’s not surprising to see hitters really struggle in the postseason with the improved pitching. Also, the hitters likely over-performed and were due for some negative regression as seen in a lower Steamer projection compared to the previous season.

The “Next Season – Steamer” column is the key data. Hitters underperform the next season by about 15 to 20 points of OPS. This difference works out to about 1 HR over 600 PA and 6 points of AVG. Not a ton but definitely a tiebreaker.

And now to the pitching data

Median Change in ERA for Postseason Pitchers
Postseason IP Postseason – Regular Steamer – Regular Next Season – Steamer Next Season – Regular
>= 25 -0.20 0.39 -0.06 0.41
20 to 25 0.01 0.66 -0.02 0.43
15 to 20 0.34 0.50 -0.18 0.23
10 to 15 -0.11 0.64 -0.18 0.46
5 to 10 -0.11 0.61 -0.06 0.54
< 5 -0.86 0.58 -0.02 0.60
Overall -0.20 0.57 -0.07 0.51

 

Average Change in ERA for Postseason Pitchers
Postseason IP Postseason – Regular Steamer – Regular Next Season – Steamer Next Season – Regular
>= 25 -0.06 0.42 -0.08 0.33
20 to 25 0.00 0.57 -0.01 0.56
15 to 20 0.57 0.48 -0.12 0.36
10 to 15 0.05 0.57 0.03 0.60
5 to 10 0.52 0.58 0.24 0.82
< 5 3.60 0.51 0.37 0.88
Overall 2.08 0.53 0.25 0.78

I didn’t expect several of these outcomes. Yes, the pitcher’s projected ERA was going to regress, but the regular to postseason results stayed almost constant using the median values. Also, the pitchers next season results were just a bit better than the projections. It even holds true for pitchers who throw a lot (> 20 IP) of postseason innings which everyone worries about.

The numbers say anywhere from a 0.05 to 0.10 lower ERA than the projections. I’m not sure what narrative(s) should explain the results. None is probably the correct answer. I’ll go with that the a pitcher who is healthy and good enough to throw a bunch of postseason innings is healthy and good enough to throw a bunch the next season.

The key is that I’m not going to ding the value of Strasburg, Cole, Greinke, Verlander, or Scherzer because of the deep post-season run. But I hope others do. For hitters, I may shy away a bit.

We hoped you liked reading Does Postseason Play Hamper Future Production? by Jeff Zimmerman!

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Jeff, one of the authors of the fantasy baseball guide,The Process, writes for RotoGraphs, The Hardball Times, Rotowire, Baseball America, and BaseballHQ. He has been nominated for two SABR Analytics Research Award for Contemporary Analysis and won it in 2013 in tandem with Bill Petti. He has won three FSWA Awards including on for his MASH series. In his first two seasons in Tout Wars, he's won the H2H league and mixed auction league. Follow him on Twitter @jeffwzimmerman.

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7 Comment authors
docgooden85SimmonsforPres2020Jeff ZimmermanDavid Chenokbjoak Recent comment authors
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antone
Member
antone

Instead of rate stat comps, how about counting stats? Are there changes in IP/PAs (due to injury or other that might have been related to an extended postseason)?

stever20
Member
Member
stever20

the innings number would be most telling. Yeah you might have been prjoected at a 3.60 era and you wound up with a 3.60 ERA, but in only 5 innings. By this analysis no difference. But in reality a huge difference.

bjoak
Member
bjoak

100% agree. People worry about overuse because of injuries to pitchers. Why not show IP?