A lot about the 2020 MLB season is uncertain.

When will it start?

How many games will be played?

Will they play at all?

If they do play, is there a chance the structure of games is modified to fit in a more representative number of games?

Let’s assume there is a season, but it’s something notably short of a full one. The fun part about a shortened season (acknowledging that we’re talking about less fun overall) is that there’s a much greater chance of a team sneaking into the playoff picture that you wouldn’t have expected. We see more upsets in five-game series than we do in seven-game series, so what about an 81-game season versus a full one?

Let’s see just how much a short season could throw things off, and how the shorter the season gets, the more chaos we might see.

For this exploration I created simulated seasons by drawing random games from the actual 2019 game-by-game results. The simulated seasons have durations ranging from 162 all the way down to 27. Because I didn’t have the time or inclination to do these simulations with fully-balanced schedules, some teams ended up with more or fewer games than the target number. To balance that out a bit, I simulated 200 seasons of each length and only used the 100 most balanced.

Once I had 100 simulated seasons of a given number of games per team, I took a rough estimate of the playoff-worthy teams by taking the top 10 teams by win percentage in each pseudo-season. Because these are all simulations anyway, I made the perfect-sphere-rolling-down-a-frictionless-inclined-plane of baseball seasons by removing divisions and just labeling the top 10 teams by win percentage as playoff caliber. Last season, for example, that would have put the Indians in the playoffs and left the Brewers out.

Here’s one way to think about how shortening the season might affect competitive balance. For each season duration, how many teams would make the “playoffs” at least once in a hundred simulations? At least ten times? Twenty?

Teams That Made the Playoffs at Least N Times in 100 Simulations

By Number of Games in Season

Season Length

Made Playoffs

Made Playoffs
10 Times
Made Playoffs
20 Times
27 Games28 Teams21 Teams15 Teams
54 Games23 Teams16 Teams15 Teams
81 Games19 Teams15 Teams12 Teams
108 Games16 Teams13 Teams12 Teams
135 Games15 Teams11 Teams11 Teams
* “Playoffs” meaning that the team ranked among the top 10 teams by Win%


So what do we get from this table?

  • Shorter seasons give bottom-feeders a fighting chance. While half the league made the “playoffs” at least once in a hundred 135-game seasons, every team but two made it at least once in a 27-game season (sorry Tigers and Marlins fans).
  • If you want something more than a fighting chance, you really do have to be a better-than-average team even in a ridiculously short season. Even in a preposterously short season, only half the league had even a one-in-five shot at making the “playoffs.”
  • If we are looking at a nice clean half season, the middle class of teams should expect to have a shot, but we should really just focus our attention on the teams that would normally be in Wild Card contention anyway.