Despite four positive tests, including three yesterday, the Miami Marlins went ahead and played the Phillies on Sunday. Today, the Marlins learned of 10 more positive tests.
40% of the Marlins' roster has tested positive.
The Marlins' home opener, scheduled for tonight against the Orioles, has been postponed. Tonight's Yankees-Phillies game in Philadelphia has also been postponed. The Orioles have returned to Baltimore, so it's likely Tuesday's games in both cities will also be postponed.
MLB's website includes a link to a statement concerning the cancellations, but nothing about the 14 positive tests.