WASHINGTON -- The Nationals and Atlanta Braves still were waiting as of Sunday afternoon to find out whether Major League Baseball will allow their upcoming series to proceed as scheduled while Washington deals with a coronavirus outbreak that could prevent 11 players from participating.

Four Nationals players have tested positive for COVID-19 over the past week and are isolating, while a total of another seven are now under quarantine because contact tracing determined they might have been exposed to the illness.

General manager Mike Rizzo said none of those 11 -- a majority of whom, although not all, were supposed to be on the opening day roster -- would be available if the three-game set with Atlanta begins Monday. Rizzo has not publicly identified any of the players involved or the two staff members who also have been placed under quarantine because of possible exposure.

Washington has yet to play a game this season; its opening three-game series against the New York Mets on Thursday, Saturday and Sunday was postponed.

"Believe me, we're in constant contact with MLB. As soon as a decision's made, they're going to let us know. They've been through this before. They know exactly what they have to do and when we when have to do this to prepare for a game on Monday," Rizzo said in a video call with reporters Sunday.

"We are preparing -- and have been preparing -- to play Monday," he said.

Team workouts have not been permitted since the outbreak began, something Rizzo says should happen before Washington faces an opponent, but pitchers were able go to Nationals Park one by one on Saturday and Sunday to throw bullpen sessions.

"Position players haven't worked out in a week. And pitchers haven't thrown any competitive pitch in that same period of time. It's something that we're taking very seriously here. We're thinking of creative ways under the protocol and under the guidance to get these guys as ready as possible," Rizzo said.

"It makes a lot of sense for baseball, player protection-wise, to have these guys go through their paces in a full workout before we take the field," he added.

The reigning NL East champion Braves are 0-3, coming off a season-opening sweep in which they managed to score a total of three runs at the Philadelphia Phillies.

And while Atlanta didn't know for certain, as of 24 hours before Monday's scheduled first pitch in Washington, when its next game would be, Braves catcher Travis D'Arnaud said: "I know we've got to be ready to play. It's better to be ready to play than get surprised."

Braves manager Brian Snitker said he was going to assume his club would be playing Monday until he hears otherwise.

"This is the COVID era. Everything's fluid," Snitker said. "If I get a call tomorrow at 10 o'clock (postponing the game), it's not going to surprise me. I'm not expecting it, but it could happen."

Rizzo said that all of his team's coronavirus testing has continued to come back negative, other than for the four players who are in isolation.

And he said those four are "feeling much, much better," adding that any symptoms that appeared earlier have subsided.

Now it is up to MLB to figure out when the Nationals can begin their season.

"We want to do everything we can to nip this thing in the bud right here, right now," Rizzo said. "So I think that's being taken very much into consideration when we're talking [about] the next couple of days."