The French defender was forced off after just five minutes in Arsenal's 1-0 defeat to Liverpool at Anfield last weekend.
He missed out on France's World Cup qualifiers during the international break, with the national side confirming he had suffered a sprained left ankle. Didier Deschamps called up Benjamin Pavard as cover.
"William Saliba, who started for Arsenal against Liverpool on Sunday, was forced off in the fifth minute. He is suffering from a sprained left ankle," a statement from the French team read. "After discussions with Franck Le Gall, Didier Deschamps confirmed the unavailability of William Saliba."
Arsenal supporters feared a lengthy absence, particularly with the team already three points behind Liverpool in the Premier League title race.
However, injury expert Stephen Smith, CEO and founder of Kitman Labs, has said there is "a huge chance" Saliba could be fit for Arsenal's crucial clash against Manchester City later this month.
Smith told the Metro: "It didn't appear to be a significant sprain, we would expect to see him back out there within two to three weeks. Everybody at Arsenal will be wiping their brow on that one because of his importance to the team."
That timeline means Saliba is likely to miss only two matches, the Premier League trip to Nottingham Forest on 13 September and Arsenal's Champions League opener against Athletic Bilbao on 16 September.
Mikel Arteta has already highlighted Saliba's influence on Arsenal's defensive stability, and the Spaniard will be eager to see him return in time for the visit of Manchester City on 21 September.
Last season, Arsenal struggled when Saliba was sidelined with a back injury during the run-in, a setback that contributed to their title challenge faltering.
This time, the Gunners will be hoping history does not repeat itself, with Saliba's availability seen as vital to their ambitions both at home and in Europe.
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