Major League Baseball commissioner Rob Manfred remains confident the 2020 season can continue, telling ESPN's Karl Ravech on Saturday that "there is no reason to quit now" despite positive coronavirus tests that have led to the postponement of 17 games in 10 days.

"We are playing," Manfred told Ravech. "The players need to be better, but I am not a quitter in general and there is no reason to quit now. We have had to be fluid, but it is manageable."

Manfred's comments follow the postponement of Saturday's St. Louis Cardinals-Milwaukee Brewers game. The postponement was caused by four positive COVID-19 tests among the Cardinals, including one player, according to ESPN and multiple reports.

Manfred on Friday told MLB Players Association executive director Tony Clark that if the sport doesn't do a better job of managing the coronavirus, it could shut down for the season, sources familiar with the conversation told ESPN's Jeff Passan.

In addition to the positive tests with the Cardinals, the league and players recognize the coming days are a critical juncture following an outbreak among the Miami Marlins in which 21 members of the organization tested positive for COVID-19.

The Marlins on Saturday reported no new positive tests, and MLB said the current plan is for the team to resume play with a four-game series against the Orioles from Tuesday to Thursday, with one doubleheader, in Baltimore. The Marlins will serve as home team for two of those games.

In other rescheduling announcements:

• The Yankees and Phillies will play a four-game home-and-home series from Monday through Thursday -- in New York on Monday and Tuesday, and in Philadelphia on Wednesday and Thursday.

• The originally scheduled game between the Yankees and Tampa Bay Rays at Tropicana Field on Thursday will be rescheduled as part of a doubleheader for next Saturday. The remainder of their four-game series on Friday and Sunday will remain as scheduled.

• The originally scheduled games between the Phillies and Marlins from this past week -- as well as the originally scheduled game between the Yankees and Orioles on Aug. 5 -- will be rescheduled for a later date.

Should another outbreak materialize, Manfred, who has the power to shut down the season, could move in that direction. Multiple players briefed on Friday's call feared the season could have been shut down as soon as Monday if positive tests jumped or if players continue not to strictly abide by the league's protocol, sources told ESPN.

In addition, networks broadcasting MLB games have been alerted to look at possible alternate programming after this weekend should a shutdown occur, sources told ESPN's Keith Olbermann.

State and local governments have pressured baseball about players skirting the mandates outlined in the league's 113-page operations manual, sources told ESPN. Broadcasts that have shown players high-fiving, spitting and not wearing masks have left government officials wondering how seriously players are taking the protocols, sources said.

Further, there is concern about off-the-field choices, with one high-ranking official saying: "There are some bad decisions being made."