Former Aston Villa defender Carlos Cuellar is reportedly in the middle of discussions with Sunderland over signing for the club.
The 30-year-old, who was released from the Midlands club at the end of the season after his contract expired, has already been linked with a switch to the Black Cats.
It is understood that the North East side have stepped up their interest and have begun negotiations with the Spaniard, according to the Daily Star.
Cuellar spent four years at Villa Park after moving from Rangers.