The report claims that Sam Allardyce wants to be reunited with the fullback regardless of what division Sunderland are in and will go in for him once his contract expires with West Ham this summer.
O’Brien, 30, played under Allardyce at Bolton Wanderers before joining the Hammers in 2011.
He helped the East London club earn promotion and consolidate themselves in the top-flight under Allardyce’s guidance, yet this season has has yet to make single league appearance.
Seemingly out of favour and unlikely to receive a new deal, O’Brien is expected to leave West Ham this summer and Sunderland are thus far the only club to be linked with his services.
The Republic of Ireland international can play on either side of defence, and his best attributes include his concentration in and out of possession and his experience when under pressure.
Sunderland currently have a number of fullbacks on their books, yet one of those is DeAndre Yedlin who is on loan from Tottenham Hotspur, so the fullback area could be one to strengthen this summer.
Allardyce will be hoping he can steer the club clear of relegation this term, but if the worst occurs and the Black Cats go down, a reliable player of O’Brien’s mould would be well-suited in the Championship.