The National League, as of now, will not use a designated hitter in 2021, but baseball will play seven-inning doubleheaders for a second straight season and begin extra innings with a runner on second base after Major League Baseball and the players’ union agreed Monday to health and safety protocols a week before spring training begins. The agreement was announced Tuesday.

The universal designated hitter could still be implemented if the league uses it later this month as a bargaining chip with the players, who favor the DH but are against the league’s idea of an expanded postseason field.

Last season’s postseason format — which included 16 teams instead of 10 — was not finalized until opening day.

The National League averaged 4.71 runs per game last season with the designated hitter after averaging 4.57 over the previous three seasons. The National League DHs hit .235 with a .728 OPS. In 2019, NL pitchers hit .131 with a .329 OPS.

But the average time of a 2020 major-league game (3 hours, 7 minutes) was the longest in history despite the new rules — universal DH, runner on second in extra innings, and three-batter minimum for relief pitchers — introduced to speed up the game.

Rosters will consist of 26 players until September, when they are expanded to 28. Last season, teams played with 28-man rosters. Road trips will again include taxi squads, which will consist of five players, one of whom must be a catcher.

MLB will use wearable contact tracing devices this season, which other leagues have used to determine whom someone had contact with if he tested positive for COVID-19. Each club must designate a “contact tracing officer” to oversee the team’s contact tracing processes and appoint a “facemask enforcement officer.”

The league will issue fines — which will be donated to charity — to players, coaches, or staff who do not wear masks in the dugout and can suspend anyone who violates the league’s new code of conduct.

Managers will no longer exchange lineup cards at home plate, but instead each club will input its lineup card into a mobile application.

During spring training, “covered individuals” — players, coaches, staff, umpires, and others — may not attend indoor gatherings of 10 or more people, indoor restaurants, bars and lounges, fitness and wellness centers, entertainment venues, or casinos.

During in-season road trips, covered individuals are not permitted to leave the hotel other than for team activities at the ballpark, outdoor walks/exercises, outdoor dining, or other low-risk outdoor activities. Covered individuals are not allowed to meet with anyone not part of the team’s traveling party and are not allowed to congregate in areas of the team hotel or enter the hotel room of another member of the traveling party.

The league says covered individuals who violate the code of conduct are subject to suspension or forfeiture of salary for days spent away from the club while in mandatory self-isolation or quarantine.

Similar to last season, players will undergo intake screenings before spring training. They will then have a mandatory five-day, at-home quarantine before reporting to camp. Individuals who test positive will be required to isolate for at least 10 days. A covered individual who is identified as a close contact of someone who tested positive will be subject to a mandatory quarantine of seven days.

If a team experiences a coronavirus outbreak, it will be allowed to temporarily add players to its roster without the need for those players to be placed on waivers, outrighted, or optioned in order to be removed from the 40-man roster when players return from the COVID-19 injured list.