Saliba was forced off with a back problem during the first of the Gunners' Europa League last-16 second leg against Sporting Lisbon on Thursday, and he subsequently missed the weekend's 4-1 win over Crystal Palace in the Premier League.
No timeframe has been placed on the centre-back's recovery by Arsenal, although reports have since claimed that he could be ruled out for several weeks, potentially putting him out of action until May.
Meanwhile, Fofana was named in the starting lineup for Chelsea's draw with Everton on Saturday, but the 22-year-old had to be taken off with 87 minutes gone.
Graham Potter was initially hopeful that Fofana was not suffering from anything more than fatigue or cramp, but he also admitted that the defender had been feeling his hamstring in a concerning update.
"Wes Fofana had to come off with fatigue, as he has had a long time out. He was feeling his hamstring. Wes was fantastic and defended well," Potter said in his post-game press conference.
As is the case with Saliba, an official update on Fofana's injury has not been delivered by his club, but France have now announced that both men will not be available for the upcoming international period.
Didier Deschamps's side have been placed in UEFA Euro 2024 qualifying Group B, and they will open with a clash against the Netherlands on Friday before a trip to the Republic of Ireland three days later.
Neither Saliba nor Fofana will be at Deschamps's disposal for those two games, though, and the Bleus boss has called up Nice's Jean-Clair Todibo and Monaco's Axel Disasi in their places.
Todido joins up with the squad as just the third uncapped player for March's matches - alongside teammate Khephren Thuram and Brice Samba - while Disasi has made three appearances for his nation at senior level.
The pair reinforce defensive ranks already boasting Ibrahima Konate, Jules Kounde, Benjamin Pavard, Dayot Upamecano and Theo Hernandez, with Presnel Kimpembe and Lucas Hernandez also out injured.
Saliba has shone for Arsenal during his breakthrough season, having been sent out on loan three times to Saint-Etienne, Nice and Marseille before earning the trust of Mikel Arteta, but Rob Holding deputised well during Sunday's win over Palace.
Saliba has two goals and one assist to show from 27 top-flight games this season, as Arsenal sit eight points clear of Manchester City - who have a game in hand - at the top of the Premier League table.
Meanwhile, Fofana's development at Leicester City and Chelsea has been hampered by a spate of physical problems, and he has been restricted to just 10 appearances for the Blues during his debut season so far.
The centre-back has already netted two goals for Graham Potter's side, who remain entrenched in 10th place, 11 points off the top four having played a game fewer than Tottenham Hotspur.