MLB knew it was taking a risk by declining to restart its season in a bubble environment with two or three hub cities, as the NBA is doing in Orlando and the NHL is doing in Toronto and Edmonton.
The plan was considered too unwieldy, many players didn’t want to be apart from their families for months, and the summer heat in Arizona, Florida and Texas was considered too oppressive to play outdoors.
So the league instead went with the option of having teams play in their own ballparks, limiting travel with regional schedules and instituting an extensive list of health and safety protocols to try and prevent players and staff from contracting COVID-19.