What a full season of seven-inning games looks like

This weekend, the Reds and Tigers played the first seven-inning doubleheader in MLB history. The shortening of games in doubleheaders is a necessity of Plagueball. With several teams unable to play because of team-wide outbreaks that would have shut the season down in any reasonable country, a myriad of doubleheaders is the only way some teams will get close to playing 60 games this year.

In a vacuum, doubleheaders are great. They were famously romanticized by Ernie Banks, but when Banks, a shortstop, said, “Let’s play two,” he didn’t have to worry about his arm falling off. Cutting the games from nine innings to seven is mostly about preserving pitchers while limiting the amount of time people have to gather at the ballpark during a pandemic. In that context, these blasphemies are easier to stomach. They’ll be gone next year never to return.

One thing that’s obvious about the 2020 season is that Rob Manfred is using the extraordinary circumstances as an excuse to try out new rules. It’s hard to see the universal DH going away now that the National League has played with it for a week and the sky hasn’t been torn asunder. The runner on second to begin extra innings likely won’t have the same staying power, but Manfred has at least made MLB fans take a “no thank you” bite.

I feel safe in saying that no one likes seven-inning baseball games. At best, seven-inning games are tolerated, so they won’t stick around. Doubleheaders are rare enough, and in normal years, expanding rosters and thus shuttling taxi squad players around isn’t inherently dangerous.

However, no one can deny that hacking two innings off a baseball game makes it shorter. For a sport that struggles to attract young audiences, that’s an enticing fact. If there’s one thing Rob Manfred knows, it’s that the Youths have fragile attention spans and the only way to draw them in is with Tik Tok-sized portions.

Because making all games seven innings is a bad idea that fails to address the issues making major league baseball worse, there’s a very real possibility Rob Manfred wants to enact it.

If this rule was ever made permanent, Manfred would never be able to extend it beyond doubleheaders, but what if he could? How would baseball change if all games, not just doubleheaders, were seven innings? What do these changes tell us about roster construction? How important are those final two innings?

It’s a complicated question, and one that I can’t possibly answer fully in a single article. So let’s start with the basics.

In 2019, there were 2,429 games played. Of those 2,429, 254 were tied after the seventh inning. In 254 games, the game was tied after seven innings or there was lead change. That’s 10.5 percent of games that needed at least the eighth and ninth innings to decide the outcome. 208 of those games went to extra innings according to Jon Tayler. That leaves us with 46 individual games where a tie was broken in the eighth or ninth innings and 46 additional games that would have gone to extra innings.

I don’t know how representative 2019 was, but it makes sense that shortening the games would lead to a greater number of extra innings games. Teams are more likely to be tied earlier in the game. In 2019’s case, there would be about 1.9 percentage point increase in extra inning contests.

We are then left with 2,175 games that would have ended after seven innings. For some teams, this would have had a profound impact on their winning percentage. Ignoring extra inning contests, the playoff picture would have been bit different in the National League. The Cubs wouldn’t have gone through a major collapse and missed the postseason, and the Diamondbacks would have made the postseason over the Cardinals. You can view the full standings here.

Below is the change in winning percentage if only leads after seven innings counted. Games that were tied after seven innings were not included. Positive values mean a team would have been better in seven-inning games whereas negative values mean a team would have been worse in seven-inning contests.

Data courtesy of Retrosheet

The Oakland A’s and the Chicago Cubs would have been the biggest beneficiaries of shortened games as the winning percentage for both would have been .050 points higher.

For the Cubs, this makes sense. Chicago’s bullpen was in pretty rough shape in 2019. They ranked 20^th in fWAR and 16^th in FIP. The midseason acquisition of Craig Kimbrel didn’t help either as Kimbrel, who mostly got the ball in the eighth or ninth, pitched dreadfully. Per Baseball Reference, the Cubs were 74-11 when carrying a lead into the eighth inning which gives them a .871 winning percentage. The rest of the majors were 1919-171 with a .918 winning percentage.

At the other end of the spectrum, the Giants would have been much worse off without the eighth and ninth innings. Until he was traded to Atlanta, the Giants relied on Will Smith to close out games, and he was quietly excellent as was the top half of San Francisco’s ‘pen. The Giants only averaged 0.34 runs allowed in the ninth. The major league average was 0.49. When the Giants took a lead or were tied going into the eighth, they usually held on or managed to scrape the winning run across before their relievers faltered.

The problem is they didn’t take that many leads into the eighth. Their offense was slow to get going and usually needed to win by attrition or in dramatic fashion. Last season, the Giants staged the largest comeback in franchise history, erasing an eight-run deficit against the Reds. It also didn’t help that for as good as Giants pitchers were in the ninth, they were equally bad in the first allowing 0.73 runs before they got the first three outs.

Only looking at the Cubs and Giants, it appears that shortened games would benefit teams with good starters and bad relievers while punishing teams with bad starters and good relievers. Of course, there are more variables that go into play. The A’s generally had an excellent bullpen but were quite bad in the later innings. If the Dodgers had a weakness, it was their bullpen and they performed worse in seven-inning games.

If games were shortened, the bulk of relief work would be subtracted from the back of the bullpen and closers like Will Smith and good Craig Kimbrel would be used in the sixth and seventh and in proportional amounts. Offense could be stifled as the talent pool of pitchers would be less diluted by middle-inning relievers. Then again, offense might rise in response if teams don’t have to carry thirteen relievers and can instead carry more specialized offensive players (pinch runners, defensively limited hitters with extreme platoon splits).

Hopefully, we never find out what a full season of seven-inning games would look like, but it’s interesting to think about how the length of the game affects strategy and what players and skills are valued.

Kenny Kelly is the managing editor of Beyond the Box Score. You can follow him on Twitter @KennyKellyWords.