The 27-year-old defender is playing well for the Black Cats at the moment and has established himself as an important player in Ross’s team.
According to WhoScored, the former Burton Albion man has made 11 starts and one substitute appearance in League One for Sunderland so far this season.
The Black Cats are second in the League One table at the moment with 40 points from 19 matches, four points behind leaders Portsmouth.
The 19-year-old forward, who is out of contract at the Black Cats at the end of the season, is wanted by Everton, Tottenham Hotspur, Southampton, Manchester City, Middlesbrough and Millwall, according to The Northern Echo.
Ross told The Chronicle regarding the future of Flanagan: "All these things you read - the stuff with Josh earlier - when you are doing well and the squad has been in a good place, you don't want to disrupt it in any way.
”I would be reluctant to lose anybody I have got in my squad at the moment because they have all played their part so far, they have all had game time and contributed in different ways. It [speculation] goes with the territory when you are doing well, so that's not such a bad thing.”