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Astros Or Braves? Flip A Coin For This World Series.

A year ago, the Houston Astros and Atlanta Braves came oh-so-close to meeting in Arlington, Texas, for MLB’s COVID-19-bubble World Series. Both teams took their respective league championship series to do-or-die Game 7s, but each fell short. This time around, nothing could get in their way: The Astros turned around the ALCS in a hurry against the Boston Red Sox, outscoring Boston 23-3 over the final three games, while the Braves got revenge for last season’s NLCS collapse against the Los Angeles Dodgers, thanks in no small part to the hot bat of Eddie Rosario all series long and the gutsy pitching of Tyler Matzek in Game 6.

And so the 2021 season will come down to Atlanta and Houston, in what looks on paper like one of the closest matchups in World Series history. According to our pre-series Elo ratings, only 5.3 rating points separates the two clubs, the 15th-narrowest gap going into any World Series:

Astros-Braves is a tightly matched World Series

Smallest differences in pre-series Elo ratings for World Series opponents, 1903-2021

Higher-Rated Team Lower-Rated Team
Year Team Elo Team Elo Elo Diff. Winner рџЏ†?
1991 Braves 1550 Twins 1550 0.1 Twins
1918 Red Sox 1547 Cubs 1546 0.3 Red Sox
2005 Astros 1558 White Sox 1557 1.5 White Sox
1930 Athletics 1582 Cardinals 1580 2.3 Athletics
1997 Indians 1537 Marlins 1535 2.7 Marlins
1962 Yankees 1558 Giants 1555 3.1 Yankees
2012 Tigers 1551 Giants 1548 3.1 Giants
1972 Athletics 1559 Reds 1556 3.8 Athletics
1922 Yankees 1566 Giants 1562 3.9 Giants
1951 Giants 1578 Yankees 1574 4.1 Yankees
1931 Athletics 1589 Cardinals 1584 4.2 Cardinals
1960 Yankees 1559 Pirates 1554 4.4 Pirates
2013 Red Sox 1576 Cardinals 1572 4.7 Red Sox
1979 Pirates 1578 Orioles 1573 4.8 Pirates
2021 Astros 1571 Braves 1565 5.3 ???
1910 Cubs 1595 Athletics 1589 5.4 Athletics
1923 Giants 1572 Yankees 1566 6.0 Yankees
1999 Braves 1588 Yankees 1582 6.0 Yankees
1966 Dodgers 1554 Orioles 1547 6.6 Orioles
2015 Royals 1549 Mets 1542 6.9 Royals

Source: retrosheet

Not only that, but our forecast model pegs the series odds at exactly 50-50 after accounting for probable starting pitchers, home-field advantage, rest and travel distance. By that standard, this matchup almost literally couldn’t get any closer. The keys to winning, then, will probably be found in the small edges each team can gain around the margins — the kinds of advantages these two clubs have evolved to press expertly throughout the year, and especially in the postseason.

At this point, Atlanta’s 2021 arc is well-known. The team was struggling early in the year even with superstar right fielder Ronald Acuña Jr. in the mix, and it seemed completely doomed when Acuña tore his ACL in July. Instead of folding, however, the Braves pulled off a series of shrewd moves that helped cover for the MVP-sized hole in their outfield — then caught fire down the stretch of the season to win the NL East and, ultimately, make the World Series.

The Braves had a recent template for a team starting slow before surging to the pennant: the 2019 Washington Nationals. That team was 12 games under .500 at its lowest point, still the fourth-biggest hole any World Series team dug out of (and No. 2 among winners). The Braves’ comeback can’t match that — Atlanta’s low point was just five games under .500 — but in other ways it was even more impressive than Washington’s recovery. 

During the 2021 regular season, Atlanta spent a total of 101 game days with a record below .500, second only to the 1973 New York Mets’ 114 sub-.500 game days among World Series teams. (By comparison, the 2019 Nats were below .500 for only 67 game days.) The 2021 Braves’ seasonlong record was also below .500 as late as its 107th game of the schedule — again, second only to the 1973 Mets (who, remarkably, were below .500 as late as their 153rd game of the year) among all-time World Series teams. Since those Mets ended up losing the World Series to the dynasty Oakland A’s in seven games, Atlanta could be the leader in each category among champions if it wins the World Series.

The Braves spent most of the season under .500

All-time World Series teams with the most total game days spent under .500 during the regular season

Year Team Last Game # Under .500 Game days Under .500 Won WS рџЏ†?
1973 Mets 153 114
2021 Braves 107 101
1914 Braves 90 90 вњ“
2005 Astros 92 77
2003 Marlins 83 72 вњ“
2007 Rockies 91 67
2019 Nationals 79 67 вњ“
2018 Dodgers 61 56
2012 Tigers 83 49
1924 Senators 52 42 вњ“
1992 Braves 55 42
2014 Royals 99 42
1969 Mets 45 41 вњ“
1979 Pirates 42 39 вњ“
1983 Phillies 94 38
1985 Cardinals 39 37
1991 Twins 49 37 вњ“
1906 White Sox 50 36 вњ“
1930 Cardinals 97 34
1951 Giants 37 33

Source: Retrosheet

But that’s all ancient history. The Braves are now peaking at the perfect moment, thanks in large part to the stellar hitting of Rosario (who boasts a ridiculous 1.313 postseason OPS) and Freddie Freeman (1.072), to go with some timely contributions from the likes of Joc Pederson, Adam Duvall, Austin Riley and Ozzie Albies.

Even more importantly, perhaps, is the fact that Atlanta’s pitchers have allowed just 3.3 postseason runs per contest to a collection of teams that averaged 4.9 runs per game during the regular season. With the exception of righty reliever Luke Jackson — who actively hurt the Braves’ chances in each of his last three appearances of the NLCS — every Braves pitcher with at least four postseason innings carries an ERA under 3.80 in the playoffs so far, with five checking in at 2.25 or better (including Matzek at 1.74 in 10в…“ innings). Building on a regular season in which it finished sixth in pitching wins above replacement,our JEFFBAGWELL metric to blend WAR from and FanGraphs, for which you can download data on GitHub.

">1 Atlanta’s staff is looking like its best weapon to help deliver a title to the most championship-starved city in major pro sports.

But Houston’s dangerous offense will have a lot to say about that. After leading MLB during the regular season with 5.3 runs per game, the Astros’ bats have become even more explosive in the playoffs so far, putting up an average of 6.7 runs per contest — or 2.4 more than we would have expected from the regular-season averages of the opposing staffs they faced. Designated hitter Yordan Álvarez has led the way, one-upping even Rosario’s performance with a postseason-high 1.329 OPS,2 and he’s one of five qualified Astro batters with an OPS north of .800 in the playoffs.

Major League Baseball teams

Related: Our 2021 MLB Predictions

Worse news for Atlanta is that two names not among that group — Michael Brantley and Alex Bregman — still had better OPS marks during the regular season than they have in the postseason, so this Astros lineup offers very few chances for opposing pitchers to relax and catch their breath. According to ESPN’s Stats & Information Group, only one team in the wild-card era (since 1995) entered the World Series scoring more runs per game in the playoffs than the Astros: the 2007 Boston Red Sox, who ended up sweeping away the Colorado Rockies in the Fall Classic.

Houston does have weaknesses, however. As good as its offense has been, it has also done a disproportionate amount of its damage in high base-out leverage situations. In the playoffs, the Astros have a batting average 79 points higher than their postseason baseline with runners in scoring position, 60 points higher than usual with two outs and 187 (!) points higher with both two outs and runners in scoring position. They’ve scored 45 runs (or more than two-thirds of their postseason total) with two outs, which is five more than the Braves have scored at all — and the most ever by a team heading into the World Series, according to research from ESPN Stats & Info. If Houston’s hitting evens out more between normal and high-leverage situations, it will make life a lot easier for the Braves’ pitchers.

And then there’s the matter of Houston’s own staff, which has been all over the place in this postseason. Astros starters have thrown only 38 of the team’s 88 total innings, leaving nearly 57 percent of the workload to a bullpen that ranked just 18th in WAR during the regular season.3 Those relievers mostly rose to the occasion, though, with the core of Cristian Javier, Kendall Graveman, Ryne Stanek, Phil Maton and Ryan Pressly combining for a 1.06 ERA in 34 postseason innings. And after allowing a shockingly high 20.25 collective ERA with Framber Valdez, Luis Garcia and Jose Urquidy going to the hill over the first three games of ALCS, Astro starters settled down with a 1.80 ERA in the series’ final three contests — including eight innings with just one run allowed by Valdez in Game 5 and 5в…” shutout innings from Garcia in the clincher. But with staff ace Lance McCullers Jr. out for the World Series, Houston’s volatile pitching situation is something Atlanta might be able to take advantage of.

Recognizing the records and legacy of Negro League baseball

It’s unquantifiable, but the Braves might also be buoyed by the fact that much of America will be rooting for the Astros to get another October comeuppance. If Atlanta’s narrative is that of the plucky underdog who picked up the pieces of its season after losing its star, the Astros’ path to the World Series is still overshadowed to an extent by the sign-stealing scandal that broke nearly two years ago and has hung over them ever since. We’ve argued before that this season’s success complicates the story around the scandal; how much of the Astros’ previous accomplishments should truly be considered “tainted” if they proved they didn’t need cheating to win? But it’s unlikely that nuance will dull the hate Houston has received over the past couple seasons. Though the Astros have plenty of likeable characters to root for — not the least of whom is manager Dusty Baker, the 72-year-old baseball lifer who played with Henry Aaron on the Braves (of all teams) and is looking for his first championship in 24 years of managing — the prospect of another Houston title would not be at the top of most fans’ rooting wish lists in this series.

Still, the Astros have a real shot at winning this World Series … and so do the Braves. After a long and winding season, we should be in store for a tightly contested championship that looks as close as any we’ve seen in a while. Who will win? Flip a coin, because it’s a 50-50 Fall Classic.

Check out our latest MLB predictions.


  1. Using our JEFFBAGWELL metric to blend WAR from and FanGraphs, for which you can download data on GitHub.

  2. Among hitters with at least 20 plate appearances.

  3. Granting that some of those innings have been filled by pitchers who often start, such as Jake Odorizzi.

Neil Paine was the acting sports editor at FiveThirtyEight.