On a day three major-league teams — including the Giants — shut their training facilities amid coronavirus outbreaks in Arizona and Florida, league officials acknowledged the need to consider alternate plans for staging a potential 2020 season. Major League Baseball owners also told the players' union they would not move off the 60-game season proposed Wednesday and would not make a counterproposal to the union's 70-game offer of Thursday. That could set the stage for owners to implement a season of whatever length they like, perhaps as few as 48 games, with players reporting to a second spring training by the end of the month and the season starting on or about July 20. In a statement, the union said it would consider "next steps." The two sides could resume talks, as players would have to approve the expanded postseason owners would like for additional television revenue over the next two seasons. "Importantly, players remain committed to getting back to work as soon as possible," the statement said. Under a March 26 agreement, Commissioner Rob Manfred has the authority to set the schedule — or to cancel the season entirely, as he has suggested he might do. The...