The Celtics' first regular-season game is set to be an Oct. 20 away tilt against the Knicks. It remains to be seen whether or not Al Horford will clear league protocols in time to return to the floor by then. David Butler II-USA TODAY Sports

Celtics center Al Horford has tested positive for the novel coronavirus COVID-19, the team announced Tuesday in a press release. Per the NBA’s coronavirus health and safety protocols, Horford is now isolating from players and team personnel.

The Celtics’ first regular-season game is set to be an Oct. 20 away tilt against the Knicks. It remains to be seen whether or not Horford will clear league protocols in time to return to the floor by then. Boston has two more preseason contests on its slate, a game Wednesday against the Magic and a contest on Friday against the Heat.

Horford was traded to the Celtics from the Thunder as part of the Kemba Walker deal earlier in the 2021 offseason. The 35-year-old big man lasted suited up for Boston during the 2018-19 season, before joining the Sixers in free agency. Horford will earn $27 million during the 2021-22 season, and is guaranteed to make at least $14.5 million of his $26.5 million salary during the final year of his deal, 2022-23.

In 28 games last season, Horford averaged 14.2 PPG, 6.7 RPG and 3.4 APG in just 27.9 MPG for the rebuilding Thunder, before Oklahoma City opted to shut him down for the home stretch of the season.

This news arrives on the heels of a recent announcement that All-Star wing Jaylen Brown also tested positive for COVID-19 over the weekend.

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