Sevilla and Valencia were also linked with Rugani but Rennes can offer a combination of Champions League football -- having qualified for the group stage for the first time -- and a regular starting spot.
They have also agreed to Juventus' demands of a €1.5 million loan fee. West Ham wanted to sign Rugani on a permanent deal but were unwilling to meet the €20m valuation.
Arsenal are willing to loan out Saliba, who is yet to play for the club following his £27m move from Saint-Etienne, with Rennes interested in bringing the defender back to France.
However, it is unclear at this stage whether Rennes would sanction deals for both Rugani and Saliba.
Speaking after Arsenal reached the Carabao Cup quarterfinals with a penalty shootout win at Liverpool, Gunners head coach Mikel Arteta said: "For many reasons, that wasn't the transition year that he needed because he had a lot of injuries, some personal injuries and also with COVID and the French league getting cancelled, he didn't have that year.
"He needs that year of transition and we are trying to make the right decisions for him to give him the best transitional year for him to have the player we want in our future."