Celtics' Al Horford tests positive for COVID-19

Boston Celtics forward Al Horford tested positive for COVID-19 and is in isolation, the team announced Tuesday, according to basketball insider Marc Stein.

Horford joins Jaylen Brown as the second Celtics player to be diagnosed with the virus in the last week. It's unclear whether either player will be available for Boston's regular-season opener on Oct. 20.

Multiple Celtics weren't vaccinated against COVID-19 just days before training camp opened, and it was unknown which players hadn't received the shot, reported Boston.com's Tom Westerholm on Sept. 26.

Horford is rejoining Boston this season after playing for the club from 2016-19. The veteran big man spent the last two years in Philadelphia and Oklahoma City.

The five-time All-Star figures to play a big role as an experienced veteran and a key cog in the frontcourt.