Rob Manfred told Tony Clark on Friday that if baseball doesn't do a better job of managing the coronavirus, it could shut down for the season, according to sources.

The league and the Major League Baseball Players Association recognize the coming days are a critical juncture following an outbreak on the Miami Marlins. Six teams were sidelined on Friday due to postponed games.

Should another outbreak materialize, Manfred has the power to shut the season down.

Friday's game between the St. Louis Cardinals and Milwaukee Brewers has been postponed, according to a source.

The Cardinals had multiple members test positive for the coronavirus.

The game was scheduled to start at 2:10 p.m. ET.

Major League Baseball and the MLB Players Association have agreed to play seven-inning doubleheaders starting Saturday, according to sources.

The compromise came together quickly with the number of doubleheaders increasing due to current and potential coronavirus outbreaks as well as weather-related postponements.

However, there are currently no double-headers on the Major League schedule. The Philadelphia Phillies were supposed to play the Toronto Blue Jays twice on Saturday, but those games were postponed after two Phillies staffers tested positive for COVID-19.

Major League Baseball and the MLB Players' Association have agreed to a new set of rules that will punish players and team personnel who steal signs electronically.

According to a document obtained by ESPN, the rules state that any individual who utilizes electronic devices or visual-enhancement devices during the game to identify, communicate or relay the opposing team's signs or pitch information will be subject to discipline.

No Houston Astros players were disciplined after an MLB investigation in January revealed an elaborate, electronic, sign-stealing scheme used by the team in 2017.

Mike Trout was placed on the paternity list by the Los Angeles Angels on Thursday.

Trout's wife, Jessica, was due to give birth to the couple's first child sometime in August. The limit for a stint on the paternity leave list is three days.

Trout will continue his Tier 1 testing schedule while he's away, which means COVID-19 tests every other day for those who are asymptomatic. So long as he continues to test negative, he can return to the Angels without interruption and would not require any sort of quarantine.

The Philadelphia Phillies have cancelled all activities at Citizens Bank Park and had their weekend series against the Toronto Blue Jays postponed, after a coach and a member of the home clubhouse staff tested positive for the coronavirus.

The Phillies said no players have tested positive.

Major League Baseball said it would coordinate with health experts and the MLBPA concerning the Phillies' return to play.

The Phillies have not played since Sunday. They are currently not scheduled to play until a four-game series against the Yankees -- in New York on Monday and Tuesday and at home Wednesday and Thursday.

Nick Markakis has reversed his opt out decision and rejoined the Atlanta Braves for the remainder of the 2020 season.

When he'll actually return to the lineup remains to be seen. The Braves must move him off the restricted list.

Markakis is the first player among the 15 that opted out to change his mind.

"I talked to my teammate and I talked to [general manager] Alex [Anthopoulos] and [manager] Snit [Brian Snitker] and all those guys," Markakis said.

"I'd like to come back. Sitting at home watching these guys compete in the last couple days and all the risks that they're taking going out there. In a way, deep down, that pit in my stomach, I felt like I needed to be out there. I had the opportunity to be welcomed back and here I am. I'm going to do my best to get back as quick as I can and help these guys out."

Major League Baseball has considered playing seven-inning doubleheaders during the shortened 2020 season.

The Cleveland Indians and Chicago White Sox played the first twin bill of the year on Tuesday.

Tony Clark called deputy commissioner Dan Halem this week and said players might want to consider shortened twin bills this year.

The players' association is surveying members and might propose either two seven-inning games for a doubleheader, or nine innings for the opener and seven for the nightcap.

MLB is checking opinions among owners and general managers, and league staff hope for a decision by Saturday to make a change or leave the rules the way the are, according to a source.

Following an outbreak of the coronavirus among the Miami Marlins, Major League Baseball has made a host of medical and safety suggestions to its teams.

The league is encouraging players not to leave hotels in road cities except for games, mandating the use of surgical masks instead of cloth masks during travel and requiring every team to travel with a compliance officer who ensures players and staff properly follow the league's protocol, according to sources.

The updated rules were outlined in a memo distributed to teams on Tuesday.

Major League Baseball has suspended Joe Kelly for eight games for his role in the benches-clearing incident that occurred at Minute Maid Park in Houston on Tuesday night.

In addition, Dave Roberts was issued a one-game suspension and Dusty Baker was fined an unknown amount.

Kelly, who threw a fastball behind Alex Bregman's head and later taunted Carlos Correa on the way back to the dugout, will appeal his suspension.

Under the 60-game format, an eight-game suspension accounts for more than 13% of the schedule.