The 40-year-old is currently asymptomatic but is self-isolating as a precaution.
Xavi was due to take charge of Al-Sadd in their first game back from the coronavirus enforced break against Al Khor later on Saturday.
The Qatar Stars League resumed on Friday, having been on suspension since May because of Covid-19.
In a statement on Instagram, the La Masia graduate and Spain legend wrote: “Today I won’t be able to join my team on their comeback to the official competition. David Prats will be there on my behalf as head of the technical staff - coach to the Al-Sadd reserves.
“A few days ago, following the QSL (Qatar Stars League) protocol, I tested positive in the last COVID19 test. Fortunately, I’m feeling ok, but I will be isolated until I am given the all clear. When the health services allow it, I will be very eager to return to my daily routine and to work. I’d like to thank all the authorities, especially those working in [the] QSL, [the] QFA (Qatar Football Association) and [at] Al-Sadd for supplying the means of early detection, reducing the spread of infection and that guarantees the normal development of the competition.
“Take care and see you soon on the football pitch!”
Al-Sadd are third on the league table, ten points behind leaders Al-Duhail, with five games to play.
Xavi won eight La Liga titles, four Champions League trophies, three Copa del Reys among other honours during his time as a player at Barcelona.
He also won two European Championships and the 2010 FIFA World Cup with Spain.
