Another Marlins player has tested positive, Major League Baseball is encouraging (but not ordering) 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 (which would seem to contradict MLB's mere "encouragement" to not wander around before or after games).
Nowhere does the 113-page protocol that governs the 2020 season explicitly address how the league would handle a coronavirus outbreak, let alone one the magnitude of the Marlins'.