NBA Commissioner Adam Silver says he does not expect the league to be able to make any decisions about its immediate future until at least May.

The NBA was the first major US professional sport league to close down due to the coronavirus, halting its season on 12 March.

Speaking on the NBA's Twitter account on Monday, Silver said the league was contemplating several scenarios surround a resumption, but the uncertainty of the pandemic made it impossible to make any firm decisions on a way forward.

"Essentially, what I've told my folks over the last week is that we just should just accept that, at least for the month of April, we won't be in a position to make any decisions," Silver said.

"And I don't think that necessarily means on 1 May we will be."

The NBA's regular season was scheduled to finish on 15 April, with the play-offs due to begin on 18 April.

While his LA Lakers had already clinched their postseason place, the NBA's biggest star LeBron James has suggested that it would be unfair to move straight to the play-offs with finishing their season, and declared himself reluctant to play without fans.

Meanwhile, Major League Baseball is reportedly exploring the possibility of restarting its season with games behind closed doors at facilities in the Arizona area.

MLB hopes the first games could occur as soon as May, according to ESPN's Jeff Passan, who added that sources indicated June might be "more realistic."

On 12 March, MLB halted spring training and pushed back its scheduled Opening Day from 26 March to mid-April. On 16 March, the start of the season was pushed back indefinitely.

Since then, team owners and the players union have discussed plans to complete as much of the 162-game schedule as possible while still following the advice of medical experts regarding the course of the COVID-19 outbreak.

The proposed Arizona plan would see games played at the Arizona Diamondbacks' home, Chase Field in Phoenix, as well as the 10 spring training stadiums within 25 miles of Phoenix.

According to ESPN, the teams and "essential personnel" would be housed in area hotels, travelling only to and from the stadiums for games.

The report stated: "Federal officials at the Centers for Disease Control and Prevention as well as the National Institute of Health have been supportive of a plan that would adhere to strict isolation, promote social distancing and allow MLB to become the first professional sport to return."

The willingness of the union to agree to have the players quarantined away from their families for an indefinite stretch is one of the many potential stumbling blocks to the proposal.

Another, according to ESPN, is concern about the health of managers, coaches and other older personnel whose risk of problems related to COVID-19 is greater is than that of the players.

Maneuvering to arrange housing, security and transportation, among other matters, amid "stay at home" orders such as the one enacted in Arizona as of 31 March further complicate the potential for the proposal to be enacted.

The Arizona Republic reported that the Phoenix-area plan was just one option MLB is exploring, with a source telling the newspaper, "They're talking about everything. There's nothing they can rule out."