BOSTON — Amid ongoing uncertainty about the COVID-19 pandemic, the Boston Athletic Association announced this week that registration for next year's Boston Marathon will not occur in September as planned.

The announcement was made just a few days before the virtual running of the 124th Boston Marathon, in which participants can run the race within a six-hour window of their choosing between Sept. 5–14. This year's in-person race was postponed, and then canceled, because of the pandemic and it appears that B.A.A. leaders remain unsure of how the health crisis could affect next year's plan.

“September is usually a time for the B.A.A. to begin opening registration for April’s Boston Marathon and planning for an already established field size. We know, however, that we cannot open registration until we have a better understanding of where the virus may be in the spring," B.A.A. CEO Tom Grilk said in a written statement.

To help plan for the race, the B.A.A. announced the formation of a COVID-19 Medical and Event Operations Advisory Group. Officials said the group will consist of medical, public safety and race operations experts. City and state officials will also participate.

“We seek to determine with some specificity how and when large-scale road running events organized by the B.A.A. may be able to reasonably resume, while also providing input on which operational aspects will change as events are organized and managed,” said Dr. Aaron Baggish, co-medical director for the B.A.A. who will also co-chair the advisory group.

"Convening this cross-sector group of professionals with decades of experience in epidemiology, viral infection, mitigation strategies, and our own race operations was entirely necessary to begin planning for the 125th Boston Marathon," said Grilk.