The NBA finally ran into a COVID-19 roadblock. The Sunday game between the Boston Celtics and Miami Heat has been postponed, the first game postponement in the year 2021.

The game between the Houston Rockets and Oklahoma City Thunder on Dec. 23 was the first game postponement of the season. This is the first postponement of 2021.

The Celtics were going to have several starters out for this game, but the league had resisted postponing the game. Sunday afternoon, the NBA decided that playing was no longer tenable.

This postponement occurs after the Philadelphia 76ers played the Denver Nuggets on Saturday despite a large number of COVID-19-related concerns on their roster. The NBA went ahead with the game, which the Nuggets predictably won.

This story involving the Celtics will generate plenty of discussion on whether the NBA should pause its season.

One of the emergent aspects of the NBA's attempt to play a pandemic season without a bubble — something the Celtics are certainly aware of at this point in time — is that the Washington Wizards have emerged as a source of COVID-19 spread.

Consider this chain of events, in which the Celtics are involved:

Given the proliferation of cross-country travel in the middle of the pandemic, at a time when COVID-19 hospitalization numbers are soaring across the United States, the Celtics and every other NBA team are seeking clarity and a greater degree of certainty on exposure levels to the coronavirus. The fact that another game has been postponed after Rockets – Thunder has the potential to make the NBA reconsider how it is handling this new season.

Many people will wonder why this season has not occurred in a bubble akin to what the NBA established in Orlando. For the Celtics and all other teams in the league, it has to be said that the bubble plan was for eight regular-season games plus the playoffs, encompassing two and a half months of game play. That's a lot shorter than a 72-game regular season and playoffs. Mental fatigue and limited mobility are significant reasons why a bubble was not renewed.