(CNN) The remainder of the shortened 2020 Major League Baseball season saw itself further imperiled Tuesday after a coronavirus outbreak on the Miami Marlins prompted the league to postpone the team's games through Sunday.
The halt to the Marlins' season less than a week after it opened follows reports by ESPN and The Athletic that four more of its players have tested positive.
"Given the current circumstances, MLB believes that it is most prudent to allow the Marlins time to focus on providing care for their players and planning their Baseball Operations for a resumption early next week," MLB said in a statement.
Miami's next six games, including Tuesday night at home against the Baltimore Orioles, have been postponed, according to MLB.
Additionally, MLB said the New York Yankees game at Philadelphia Tuesday evening and the Philadelphia Phillies' games in the Bronx on Wednesday and Thursday were postponed "out of an abundance of caution."
The Yankees will now play the Baltimore Orioles at Camden Yards on Wednesday and Thursday "to create more scheduling flexibility later in the season," MLB said.
Eleven Marlins players and two coaches had previously tested positive for the virus, according to ESPN.
Within the last week, ESPN reported, the team has had 17 people test positive. The delayed season began on Thursday.
CNN has reached out to the Marlins and MLB for confirmation on the new cases.
In a statement, Marlins CEO Derek Jeter said the team is "having a difficult time enduring this experience" while isolating and quarantining in Philadelphia.
Jeter said the team has "moved to a daily testing schedule" and enacted "additional preventive procedures with our traveling party."
The team did not travel back to Miami Sunday after a three-game series in Philadelphia, but stayed overnight for more testing.
The Marlins' home opener against the Orioles and the Yankees game with the Phillies on Monday evening were also postponed.
On Monday, MLB commissioner Rob Manfred said whether a league or team would have to shutdown would depend on the circumstances.
"I think that a team losing a number of players that rendered it completely non-competitive would be an issue that we would have to address and have to think about making a change, whether that was shutting down a part of the season, the whole season, that depends," Manfred said.
"Same thing with respect to league-wide. You get to a certain point league-wide where it does become a health threat and we certainly would shut down at that point."
Ahead of the Marlins' game Sunday against the Phillies, the Marlins found out that starting pitcher Jose Urena would not be available to play.
On Tuesday, the Marlins told CNN that the team had alerted the league and the Phillies of the team's "positive tests" before Sunday's game. The Phillies "concurred to play," according to the Marlins.
Urena had tested positive for Covid-19, according to multiple outlets, including ESPN and The Philadelphia Inquirer.
But the players decided in a group chat to play the game anyway, Marlins shortstop Miguel Rojas said in a video call with reporters.
"We made the decision that we're going to continue to do this, and we're going to continue to be responsible and just play the game as hard as we can," Rojas said.
The Marlins went on to win the game, 11-6.
MLB said Tuesday there had been no new positive results involving on-field personnel from any of the other 29 clubs in more than 6,400 tests conducted since Friday.
"This outcome is in line with encouraging overall data since the June 27th start of testing," the statement said. "Through last Thursday ... 99 of the 32,640 samples -- 0.3% -- had been positive."
Florida over the weekend became the state with the second-highest official coronavirus case count, surpassing New York -- the country's epicenter early in the pandemic.
The return of professional sports couldn't have come at a worse time as cases in the US continue to rise, with more than 4 million confirmed cases, according to Johns Hopkins University data.
The abbreviated, 60-game MLB season is spectator-free. It features new rules, including the banning of spitting, to avoid spreading the virus.
Like baseball, the National Football League plans to begin its season at teams' regular home stadiums. NFL Commissioner Roger Goodell wrote in an open letter Monday that preseason games were canceled.
Other sports leagues are reopening with teams in so-called "bubbles" to limit interactions with the outside world.
The WNBA tipped off its season on Saturday at IMG Academy in Florida. The NBA is set to restart its season later this week at ESPN Wide World of Sports Complex in Orlando, and the NHL is planning to restart with dual bubbles in Toronto and Edmonton. In Utah, the NWSL Challenge Cup wrapped up Sunday, with the Houston Dash winning the title.