Boston Marathon organizers said Wednesday that the 2021 race won't be run on Patriots Day because of the coronavirus pandemic, the second straight year that it has been moved from the April weekend that was its home for more than a century.

About six months before the scheduled April 19 date, the Boston Athletic Association said it was postponing next year's race until "at least the fall of 2021," conceding that the state won't have sufficiently emerged from the pandemic to allow as many as 30,000 runners and a half-million fans to gather on the streets from Hopkinton to Copley Square in the spring.

"We are unable to host the Boston Marathon this coming April," BAA CEO Tom Grilk said in a statement. "We are optimistic that the Boston Marathon will continue its tradition of celebrating the spirit of community and athletic excellence next fall."

Organizers said they hope to work with state and local officials to "determine if a fall 2021 date is feasible." The BAA said it hopes to select a fall date by the end of the year.

The 2020 Boston Marathon was originally postponed from April to September, but it was cancelled outright two months later — the first time since 1897 that there was no in-person Boston Marathon of any sort.

A total of 15,972 people ran a "virtual" race this year, completing the 26.2-mile distance on their own over a 10-day period. In 1918, the format was modified to a relay due to World War I; the 2013 race was stopped when two bombs exploded at the finish line, several hours after the winners had finished but while many recreational runners were still on the course.

"There is a pretty rich history of accommodation and addressing reality," Grilk said at the time. "This is this year's reality."

Massachusetts' reopening plan doesn't allow road races until Phase 4, which would require the widespread availability of a vaccine or treatment.