OPINION: 7-inning Doubleheaders Need To Go

During the shortened 2020 season, MLB and the MLBPA agreed to a rule that made each game of doubleheaders seven innings. Then, during this past offseason, they agreed to keep that rule for the 2021 season. Not only do some players and managers dislike the rule, it creates an imbalance in the schedule, with some teams playing fewer innings than others. Another side effect of the rule is a possible increase in the number of doubleheaders, which will further imbalance teams’ schedules. By changing the number of innings in some games, 7-inning doubleheaders change both in-game and seasonal strategy, and MLB should revert back to traditional 9-inning doubleheaders.

While there were some positive reactions to the rule, many managers and players, particularly those that played in many of the new shortened games, did not like the new rule. In “This year, MLB pennant races will be decided nine innings at a time — or sometimes seven,” Dave Sheinin discusses the rule and quotes Miami Marlins manager Don Mattingly, who said, “Seven innings doesn’t feel like a full game to me.” And it isn’t. MLB has been playing 9-inning games since 1856, so seven innings is not a full game at the highest level. Mattingly’s opinion on the matter is important, as the Marlins’ COVID-19 outbreak forced them to take part in a league-leading 8 doubleheaders in the 2020 season.

Because fewer innings are being played, 7-inning games are played faster, which could encourage the league to play more of them. According to Sheinin, of the first 35 doubleheaders (70 total games) in 2020, 65 of the games ended in seven innings. The average time of game for those 65 games was 2:34, over 30 minutes shorter than the average 9-inning game at that point for the 2020 season. MLB commissioner Rob Manfred has repeatedly said he wants to shorten the length of games, with rules such as the no-pitch IBB and pitch clock designed to accomplish that, so he would definitely be in favor of more 7-inning games. But middle relievers, such as veteran Adam Ottavino, are afraid they could lose their role in the game. With middle relief becoming more of a specialized position in recent years, Ottavino said, “I don’t want to be marginalized out of the game.” If the league does schedule more doubleheaders, games’ outcomes begin to be decided by that scheduling rather than just the teams on the field.

Goodman Table I (Doubleheaders)

In “On the Incidence of Swept Double-Headers,” Michael Goodman analyzed the 1964 MLB season, looking at doubleheaders (Table I) and sets of two games played between the same teams on consecutive days (Table II). Many people back then, and even today, believed that it was very difficult for a doubleheader to be swept. The problem is that splits are often double-counted, so it looked like there were 162 splits in 1964, when there were actually only 81, compared to 113 sweeps. Using 95% confidence intervals, Goodman was able to show that doubleheaders were actually swept more often than split. Not only that, but he also proved that doubleheaders were more likely to be swept than a regular two-game series against a team. To do this, he split up games into three categories; regular 2-game series, pairs of games before or after a doubleheader in a 4-game series, 4-game series played across four days (which was split into two, 2-game series). No 3-game series were included as the middle game would be double-counted. Those were pretty even but actually split much more often than doubleheaders, with 119 sweeps and 126 splits. Therefore, if more doubleheaders are played, it is more likely that one team wins both of the games.

Goodman Table II (2 game series)

7-inning doubleheaders also increase the randomness, making it even more difficult for the best team to separate themselves. MLB is already the most random of the four major US sports, as evidenced by the need for a 162-game schedule and the advance rate of superior teams in the playoffs. Michael Lopez looked at this in “Part II: Rethinking Our Playoff Philosophy (on the Role of Chance in the Postseason).” In baseball, the better team advances about 60% of the time in a 7-game series, compared to about 80% in the NBA. For MLB to match that mark, they’d need to go to a best-of-75 game series. With more 7-inning games, there’d be less time on the field, allowing the better team to win even less often.

How often the better team advances (Lopez)

While they may have been necessary last year due to the shortened season and COVID changes, MLB needs to get rid of the 7-inning doubleheaders. Not only is a 9-inning game one of the fundamental parts of baseball, 7-inning doubleheaders also increase the likelihood of a worse product and affect the results on the field. So far this year, 9 of the 22 7-inning games have been decided by 1 run, with 2 going to an “extra” inning in the 8th. In a normal game, those teams would have a good chance to tie the game up in the last two innings; instead, it was a disappointing loss that could come back to hurt in October. Baseball is already one of the most random sports, which is one reason why it has the longest schedule, and less time on the playing field will only make that problem worse. Because of that, Major League Baseball needs to get rid of the new 7-inning doubleheader rule and go back to 9-inning doubleheaders as it has always been throughout the history of the sport.

Note: As the article was being finished, Madison Bumgarner threw a 7-inning “notable achievement,” which is what MLB officially calls a no-hitter in a 7-inning game, so that’s another reason we need to get rid of 7-inning games.


Goodman, Michael L. “On the Incidence of Swept Double-Headers.” The American Statistician, vol. 23, no. 5, 1969, pp. 15–17. JSTOR, www.jstor.org/stable/2682179. Accessed 3 Apr. 2021.

Lopez, Michael. “Part II: Rethinking Our Playoff Philosophy (on the Role of Chance in the Postseason).” Statsbylopez, 22 Aug. 2018, statsbylopez.netlify.app/post/part-ii-randomness-of-series/.

Sheinin, Dave. “Analysis | This Year, MLB Pennant Races Will Be Decided Nine Innings at a Time – or Sometimes Seven.” The Washington Post, WP Company, 13 Sept. 2020, www.washingtonpost.com/sports/2020/09/11/mlb-seven-inning-doubleheaders/.

Matthew Penn

Graduate student with a degree in Sport Analytics. Lifelong Nationals fan trying to bring an analytical analysis to baseball. On twitter @matthewhpenn

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