As Opening Day of the 2021 MLB season approaches, fans across the country will soon return to their home teams' ballparks -- in most cases for the first time since the coronavirus pandemic began.

But there will be limitations -- particularly when it comes to capacity -- that won't be uniform across the league. State and local governments will have a lot of say in determining how many fans can safely attend live sporting events (if any), a figure likely to change with fluctuations in the spread of COVID-19 and vaccination rates.

Last season, all regular-season games and most postseason contests were played in front of empty stands. During the National League Championship Series and World Series, both held at Globe Life Field in Arlington, Texas, fans were allowed to attend in limited numbers representing about 28% of the stadium's full capacity.

While firm plans haven't yet been released by all 30 MLB teams, here's the latest on what we know about each individual club's plans, proposals and protocols.

We'll keep this file updated as more details become available.

Arizona Diamondbacks

Chase Field

Home opener: April 9 vs. Reds

Fans allowed on Opening Day? Yes

How many? Approximately 12,000 (25% capacity)

What you need to know: The Diamondbacks recently received approval to allow for 25% capacity at their Phoenix stadium to begin the season, and they will do so with pod seating separated by six feet. The team began offering those seats to season-ticket holders dating back to the start of February in anticipation of eventually getting approval. D-backs president and CEO Derrick Hall, speaking during Fox Sports Arizona's broadcast of Sunday's spring training game against the Cubs, said: "Hopefully, things will go smooth, we'll see these numbers continue to go down and we can offer many more seats in the second, third, fourth month, if we can."

Atlanta Braves

Truist Park

Home opener: April 9 vs. Phillies

Fans allowed on Opening Day? Likely

How many? TBD

What you need to know: Fans are expected to be allowed to attend games, the Braves said, but the team has yet to provide specifics on capacity restrictions. More details are expected by mid-March.

Baltimore Orioles

Oriole Park at Camden Yards

Home opener: April 8 vs. Red Sox

Fans allowed on Opening Day? TBD

What you need to know: The Orioles are in discussions with local public health officials but have not announced any concrete plans for welcoming fans in 2021. Daily COVID-19 positive rates in the state of Maryland were at 3.9% on Sunday, down from 5.3% a month earlier.

Boston Red Sox

Fenway Park

Home opener: April 1 vs. Orioles

Fans allowed on Opening Day? Yes

How many? Approximately 4,500 (12% capacity)

What you need to know: Massachusetts Gov. Charlie Baker announced Feb. 25 that the state would enter into Phase 4 of its reopening plan in late March, which would allow the Red Sox to operate at 12% capacity by the start of April. Fenway Park will stop functioning as a mass vaccination site before then. The team will announce more detailed plans regarding ticket rollouts and health and safety protocols at a later date.

Chicago Cubs

Wrigley Field

Home opener: April 1 vs. Pirates

Fans allowed on Opening Day? Yes

How many? Approximately 8,300 (20% capacity)

What you need to know: The Cubs and White Sox made a dual presentation to the city of Chicago and state of Illinois proposing 30% capacity to start the season. They got approval for 20% on Monday. The proposal included contactless payment and mobile ticketing, plus socially distanced seating.

Chicago White Sox

Guaranteed Rate Field

Home opener: April 8 vs. Royals

Fans allowed on Opening Day? Yes

How many? Approximately 8,100 (20% capacity)

What you need to know: The Sox and Cubs requested 30% capacity but were approved for only 20%. The Sox will have seating pods from one to six fans, will add numerous hand sanitizing stations around the park and will prohibit bags except for small clutch purses, medical bags or diaper bags when infants are present.

Cincinnati Reds

Great American Ballpark

Home opener: April 1 vs. Cardinals

Fans allowed on Opening Day? Yes

How many? Approximately 12,700 (30% capacity)

What you need to know: The Reds are allowing 30% capacity to start the season with typical social distancing measures in place, including smaller pod seating, contactless forms of payment and a mask mandate, unless actively eating or drinking. Backpacks will be banned, as well.

Cleveland Indians

Progressive Field

Home opener: April 5 vs. Royals

Fans allowed on Opening Day? Yes

How many? Approximately 10,500 (30% capacity)

What you need to know: The Indians are allowing 30% capacity to start the season and will work month to month on increasing max attendance. Season-ticket holders will get priority access to ducats in pods of two or four. Usual social distancing measures will be implemented in addition to cashless transactions. Gates will open one hour before first pitch.

Colorado Rockies

Coors Field

Home opener: April 1 vs. Dodgers

Fans allowed on Opening Day? Yes

How many? Approximately 12,500 (25% capacity)

What you need to know: The Colorado Department of Public Health and Environment approved a 25% capacity at Denver's Coors Field beginning on Opening Day, with concrete plans forthcoming. In a statement, the Rockies said conditions will continue to be monitored, "with the hope of safely adding to the capacity number in the future."

The Rockies have launched an informational page on their website outlining the safety protocols that will be put in place at Coors Field, including reverse ATMs for cashless transactions and a strict mask policy. Following MLB rules, players will not be allowed to sign autographs or toss baseballs into the stands.

Detroit Tigers

Comerica Park

Home opener: April 1 vs. Indians

Fans allowed on Opening Day? Yes

How many? 1,000

What you need to know: Right now, the Tigers are allowed to have more fans -- 2,000 -- at their spring training site in Florida than will be allowed (1,000) in Detroit. State guidelines are preventing them from having more, but in an ever-changing landscape, the numbers could increase before Opening Day. With so few fans inside Comerica Park, socially distanced seating in pods should not be hard to maintain.

Houston Astros

Minute Maid Park

Home opener: April 8 vs. A's

Fans allowed on Opening Day? Likely

How many? TBD

What you need to know: Texas Gov. Greg Abbott issued an executive order on March 2 that lifted the state's mask mandate and allowed all businesses and facilities to open at 100%. That gives the Astros the ability to welcome fans at full capacity to begin the season, but the team is still evaluating its plans and hopes to have those finalized by the end of the week.

Kansas City Royals

Kauffman Stadium

Home opener: April 1 vs. Rangers

Fans allowed on Opening Day? Yes

How many? Approximately 10,000 (30% capacity)

What you need to know: The Royals will start the season allowing 30% capacity, with plans to increase attendance monthly. Season-ticket holders will have priority access to tickets beginning this week, while the general public will get their chance to purchase them for the first month of the season beginning March 24. Kauffman Stadium has been reconfigured for pod-style seating.

Los Angeles Angels

Angel Stadium of Anaheim

Home opener: April 1 vs. White Sox

Fans allowed on Opening Day? Likely

How many? Approximately 8,650 (20% capacity)

What you need to know: Orange County is expected to soon move from the Purple tier to the Red tier, which, under California Gov. Gavin Newsom's recent mandate, would allow MLB stadiums to operate at 20% capacity as of the start of April. The Orange tier would increase the capacity to 33%, and the Yellow tier would move it to 67%. The Angels have yet to announce specific plans on safety protocols or ticket distribution.

Los Angeles Dodgers

Dodger Stadium

Home opener: April 9 vs. Nationals

Fans allowed on Opening Day? Likely

How many? Approximately 11,200 (20% capacity)

What you need to know: The Dodgers said Friday they would announce specifics around ticket policy and health and safety protocols "in the coming days." California Gov. Newsom announced earlier that Red tier counties can host fans at MLB stadiums at 20% capacity beginning in April, validating the optimism expressed by Dodgers president and CEO Stan Kasten a few weeks earlier. Los Angeles County is projected to move from the more restrictive Purple tier to the Red tier soon.

Miami Marlins

Marlins Park

Home opener: April 1 vs. Rays

Fans allowed on Opening Day? Yes

How many? Approximately 9,200 (25% capacity)

What you need to know: The Marlins are allowing 25% capacity to begin the season, with digital-only access to tickets. Free-flow parking will be instituted to allow contactless payments. Ticket holders will have a time and gate for entry into the ballpark with usual social distancing guidelines being adhered to. Mobile, preordered food from concession stands will be allowed to reduce lines in the concourse.

Milwaukee Brewers

American Family Field

Home opener: April 1 vs. Twins

Fans allowed on Opening Day? Yes

How many? Approximately 10,475 (25% capacity)

What you need to know: The Brewers are allowing 25% capacity beginning on Opening Day. They hope to "work toward increasing the capacity if the health metrics continue to improve," according to Brewers president of business operations Rich Schlesinger. Usual social distancing practices will be implemented, including "right way" walking through the concourse. Attendees can only watch the game from their assigned seats, while congregating near the first two rows of the field is prohibited.

Minnesota Twins

Target Field

Home opener: April 8 vs. Mariners

Fans allowed on Opening Day? Maybe

How many? Current goal is approximately 10,000 (25% capacity)

What you need to know: Talks are ongoing after the Twins put forth an initial proposal to state officials.

New York Mets

Citi Field

Home opener: April 8 vs. Marlins

Fans allowed on Opening Day? Yes

How many? Approximately 4,200 (10% capacity)

What you need to know: New York Gov. Andrew Cuomo announced Feb. 10 that stadiums seating at least 10,000 fans can open at 10% capacity, giving the Mets and Yankees the green light to welcome fans at the onset of the 2021 regular season. Per state guidelines, staff and spectators must receive a negative COVID-19 test within 72 hours of an event in order to attend. The teams are still working through details on the protocols that will be implemented.

New York Yankees

Yankee Stadium

Home opener: April 1 vs. Blue Jays

Fans allowed on Opening Day? Yes

How many? Approximately 5,400 (10% capacity)

What you need to know: See Mets above. (The Yankees, for their part, called the governor's announcement "an encouraging first step" in a statement.)

Oakland Athletics

Oakland Coliseum

Home opener: April 1 vs. Astros

Fans allowed on Opening Day? Likely

How many? Approximately 9,400 (20% capacity)

What you need to know: In anticipation of Alameda County soon moving into California's Red tier, the A's announced several policies and protocols that will be in place for fans to return to the Oakland Coliseum, beginning at 20% capacity, including: pod seating in groups of two or four; ticket sales restricted to California residents; face masks required at all times, except when eating or drinking; mobile-only ticketing and cashless transactions; concession items ordered only through smartphones; and no tailgating.

Philadelphia Phillies

Citizens Bank Park

Home opener: April 1 vs. Braves

Fans allowed on Opening Day? Yes

How many? Approximately 8,600 (20% capacity)

What you need to know: Seating pods at 20% capacity will be for two, three or four people, with limited pods available for five or six. Only tickets for the first 19 games, through early May, will be available initially. Tickets for the rest of the home schedule will go on sale in early April with a hope to increase attendance by then. All areas of the ballpark accessed by fans will be cleaned and disinfected before, during and after each game by a newly created "Clean Team" utilizing processes and products approved by the Centers for Disease Control and Prevention and the Environmental Protection Agency, specifically for use against COVID-19. Hand sanitizing stations also will be widely available.

Pittsburgh Pirates

PNC Park

Home opener: April 8 vs. Cubs

Fans allowed on Opening Day? Yes

How many? Maximum of 7,600 (about 20% capacity)

What you need to know: PNC Park will allow for 20% capacity, but that includes everyone inside the stadium -- including employees. The Pirates have yet to announce how many fans will be part of that 20%. Usual social distancing and pod seating protocols will be part of the guidelines when they are announced.

San Diego Padres

Petco Park

Home opener: April 1 vs. Diamondbacks

Fans allowed on Opening Day? Likely

How many? Approximately 8,000 (20% capacity)

What you need to know: San Diego County will be given the green light to host fans at 20% capacity at Petco Park so long as it moves from California's Purple tier to the Red tier by the end of March, and current trends support that possibility. As part of a statement, Padres CEO Erik Greupner wrote: "We expect that Padres fans will be able to support our team in-person beginning on Opening Day." Season-ticket holders will receive priority access to games, the Padres announced, as will undoubtedly be the case for every team.

San Francisco Giants

Oracle Park

Home opener: April 9 vs. Rockies

Fans allowed on Opening Day? Yes

How many? Approximately 8,250 (20% capacity)

What you need to know: San Francisco is currently operating in California's Red tier, which, under the new mandates from the governor, would give the Giants the ability to host fans at 20% capacity. "In the coming days," the team said Friday, "the Giants will submit our operational plans for review and approval by the local health officials and we eagerly look forward to safely welcoming fans back to Oracle Park."

Seattle Mariners

T-Mobile Park

Home opener: April 1 vs. Giants

Fans allowed on Opening Day? TBD

How many? TBD

What you need to know: The Mariners are in contact with local health officials and remain hopeful about the possibility of welcoming fans early in the season. New York Times data recently showed that King County, which includes Seattle, has the second-lowest COVID-19 rate among the 100 most-populated counties in the United States.

St. Louis Cardinals

Busch Stadium

Home opener: April 8 vs. Brewers

Fans allowed on Opening Day? Yes

How many? Approximately 14,600 (32% capacity)

What you need to know: The Cardinals are allowing 32% capacity to begin the season. Social distancing rules will apply, with pod seating of four or fewer fans. Cashless transactions and mobile ticketing will be required by those wishing to attend. There will be six designated entry and exit gates, with no reentry allowed. Only medical or diaper bags will be allowed in the ballpark. Season-ticket holders will be allowed first opportunity to secure tickets to the first two homestands.

Tampa Bay Rays

Tropicana Field

Home opener: April 9 vs. Yankees

Fans allowed on Opening Day? Likely

How many? Probably 7,000 (16% capacity)

What you need to know: The Rays said earlier in the year they hoped to accommodate 7,000 fans a game, and there has been no word since on whether that number has changed. The Rays also scrapped season-ticket locations in an effort to ensure socially distant seating, announcing instead a model that allows fans to choose from six "season membership" levels, with prices ranging from $500 to $20,000.

Texas Rangers

Globe Life Field

Home opener: April 5 vs. Blue Jays

Fans allowed on Opening Day? Likely

How many? TBD

What you need to know: The Rangers hosted fans at Globe Life Field for two postseason rounds in October, limiting capacity to roughly 11,000 fans (less than 30% capacity). In a statement issued last week, Rangers COO Neil Leibman said he was "encouraged" by Texas Gov. Abbott's executive order lifting the state's mask mandate and allowing businesses to operate at 100% capacity, adding that the team "will work through the necessary operational logistics to put the required protocols and health measures in place."

Toronto Blue Jays

TD Ballpark (Dunedin, Florida)

Home opener: April 8 vs. Angels

Fans allowed on Opening Day? Yes

How many? Approximately 1,275 (15% capacity)

What you need to know: The Jays will play their first two homestands at their spring training facility because of Canadian government restrictions during the coronavirus pandemic. Capacity will be limited to 15% at their renovated facility, which seats 8,500 under normal circumstances. Blue Jays president Mark Shapiro said Feb. 18 that the team might move back to Sahlen Field in Buffalo, New York (where the Jays played the majority of their home games last season), around June to avoid the heat and humidity in Florida. The hope is that the Blue Jays will then return to Rogers Centre in Toronto for the second half of the season.

Washington Nationals

Nationals Park

Home opener: April 1 vs. Mets

Fans allowed on Opening Day? No -- for now

What you need to know: While the Nats were approved to open their ballpark this season by the District of Columbia Homeland Security and Emergency Management Agency, no fans will be allowed. However, the rate of the virus' spread and the vaccination rate could change that. News on ticket sales to fans is expected in mid-March.