ATC 2021 Projected Standings and Playoff Odds

Earlier this year, we released our team expected win totals and playoff odds for the 2021 season. These projections are based on the FanGraphs Depth Charts, which blend Jared Cross’ Steamer projections with those of Dan Szymborski’s ZiPS, with playing time allocated by our own Jason Martinez of RosterResource fame; the playoff odds then simulate the season 20,000 times, taking strength of schedule into account.

We thought it’d be interesting to duplicate that process, instead using the Average Total Cost (ATC) Projections.

The ATC player projections have been available on the pages of FanGraphs since 2017. Similar to the Depth Charts model, ATC is an aggregation of other projections. While most other accumulation models typically apply equal weight to all their underlying data sources, ATC assigns weights based on historical performance. The method is similar to what Nate Silver does with his political forecasting model at FiveThirtyEight.com. You can read more about how ATC works in the introductory article here.

Over the past few years, ATC has consistently been one of the most accurate baseball forecasting models. Indeed, according to FantasyPros, the ATC projections have been the most accurate baseball projections over the past two seasons. The success of ATC stems from minimizing parameter risk across the player pool. You can read more about inter-projection volatility, how to use the ATC projections on the FanGraphs site, and what is new for ATC in 2021 here.

Without further ado, here are the ATC forecasted win totals:

And here are the simulated standings and playoffs odds:

Let’s take a quick look at some of the differences between the engine results for the ATC projections and the FanGraphs playoff odds.

The ATC projections are more bullish on the Brewers’ chances in 2021, putting the odds of Milwaukee making the playoffs at 67% versus the FanGraphs Depth Charts projections figure of 39%. The FanGraphs playoff odds sees the NL Central as a wide-open division. Other than the lowly Pirates, each team is projected for at least a 22% chance at playing in the postseason. On the other hand, ATC models the Brewers as the clear favorites – with an expected five game advantage over the next best squad, the Reds.

At the other end of the spectrum, ATC has a vastly different view of the American League West. The ATC projections forecast the Athletics and Angels for five fewer wins apiece in 2021, placing the chances of making the playoffs at just 18% for Los Angeles and 15% for Oakland; the Depth Charts projections give roughly double those odds (37% and 34% respectively). At the top of the AL West, ATC projects the Astros to win one additional game versus the Depth Charts projection, enough to elevate Houston’s chances of a postseason berth from 70% to 87%.

The full win total disparity between the two projection engines can be seen below:

Both projections place the Dodgers, Padres and Yankees as the teams with the highest probability of reaching the postseason. ATC gives a slight edge to the Yankees over the Padres, with all three teams garnering at least a 90% chance to play an official 163rd game in 2021.