Saliba will play for the Gunners next season after returning to St. Etienne on loan for the 2019/20 campaign.
Mikel Arteta is looking at a number of centre-backs to partner with the young Frenchman.
And Metro says the Gunners scouting team have been impressed by Wesley Fofana whilst keeping an eye on Saliba's progress.
The 19-year-old made 14 appearances for the Ligue 1 club.
St. Etienne are seeking a replica of the Saliba deal, which will see Fofana sold then loaned back to the club for a season.