The season was due to have begun in March, but the pandemic prevented that from happening and a dispute between owners and players over how to proceed followed.

An agreement was eventually reached to play a 60-game regular season, which began yesterday between the Nationals - the defending champions - and the New York Yankees. 

The Yankees won a rain-shortened game overshadowed by Soto's absence 4-1.

Said to be asymptomatic, the 21-year-old will have to test negative twice before he can play again.

Soto has his 61 home runs in two seasons - including three in last year's World Series - and was named to the 2019 All-MLB Second Team.

While there are firm testing protocols in place, some have raised concerns over playing baseball given the current infection rate in the United States and the time lag between taking a test and receiving results.

It has taken some players multiple weeks to be cleared for a return after testing positive for COVID-19.

Dr Anthony Fauci, the immunologist leading the US response to COVID-19, threw the ceremonial first pitch in the American capital.

It certainly wasn't a strike.

The other game on Opening Day saw the Los Angeles Dodgers beat the San Francisco Giants 8-1.

Mookie Betts, who earlier this week signed the second-richest contract in baseball history, made his Dodgers debut and scored a run.

Betts was also among a group to kneel for the national anthem to protest racial injustice and police brutality.

All games are being staged behind closed doors.

The season continues today, although the Toronto Blue Jays - denied permission to play in Canada by the Government - are still looking for a home.

MLB is the first of the major American sports leagues to resume, with the National Basketball Association and National Hockey League both poised to follow suit shortly.