The two clubs are in talks over a possible move to the Stadium of Light for the Brazil international, probably on loan.
It is the first approach Rangers have received for Cesar, 34, despite numerous clubs being linked with him since the end of last season.
He was keen to stay in London and join Arsenal in the summer but the Gunners showed no real interest despite reports they were battling to sign him.
Supposed interest from a number of European clubs also came to nothing.
But Sunderland boss Gus Poyet is open to signing Cesar, who is available on a free transfer.
Cesar, who has recently been linked with Southampton, moved to Loftus Road from Inter Milan last year.