DENVER – The Twins open the second half of the season Friday with a doubleheader in Detroit, a seven-inning rainout makeup in the afternoon and seven more regularly scheduled innings in the evening.

Commissioner Rob Manfred hopes it never happens again.

"I don't think seven-inning doubleheaders are going to be part of our future," Manfred said Tuesday in an appearance at the semiannual meeting of the Baseball Writers Association of America. The decision to extend the 2020 rule change for another year was made before spring training opened, when the distribution of COVID-19 vaccinations was in doubt and many pandemic restrictions remained in place.

"At the time we made that decision, we did not know the country was going to look like it looks right now. As a matter of fact, we were scared it was going to look very different," Manfred said. "Might we have done it differently? Maybe."

With no fans in stadiums last year, the games were shortened to reduce players' exposure. Now with all stadiums open again, teams have scheduled "split" doubleheaders, requiring separate admissions, despite playing two fewer innings. The Twins, with a rainout to make up against Cleveland, have scheduled such a doubleheader at Target Field on Sept. 14.

Manfred said he is sensitive to questions of fairness to fans, but offering adjustments — refunds, or concession credits — on a leaguewide basis is unlikely.

"Those are things that sound easy that are a lot harder to execute in real life," he said. "The important point is, we understand it's an issue. We don't see these doubleheaders as part of our long-term future."

Another change to Major League Baseball introduced last year as a result of the pandemic was beginning all extra innings with a runner on second base; like the seven-inning doubleheaders, that rule was already in place in the minor leagues. Manfred indicated that rule, too, would likely be done away with in the majors next year. The Twins have played 13 extra-inning games this season; all but one was decided in the 10th inning.

One rule change that has yet to be implemented is limiting defensive shifts. Manfred strongly hinted he supports that, probably requiring two infielders to be stationed on either side of second base.

"It makes the game look like what it looked like when I was 12 years old watching the All-Star Game at camp. So it's not change; it's kind of restoration," Manfred said. "That's why people are in favor of it. I do believe and I think front offices in general believe it would have a positive effect on the play of the game."

As for MLB's current initiative, a crackdown on foreign substances applied on the baseball by pitchers, Manfred said the policy appears to be having a positive effect.

"Batting average, slugging percentage, all those kinds of categories have improved. Strikeouts are down, bases on balls are down. All those things are improvements," he said. "Players overwhelmingly supported what we have done."