Middlesbrough have made a bid of over £5m for Sunderland midfielder Paddy McNair, according to Sky sources.
Sky Sports News understands Sunderland have previously turned down two bids from Brighton for the 23-year-old, with the second of those for £3.5m.
In addition, it was also understood the club had turned down an offer of £3.75m for McNair from an unnamed London side.
McNair made 18 appearances and scored five goals last season as Sunderland were relegated from the Championship.
The Northern Ireland international broke into Manchester United’s first team in 2014 before joining Sunderland in August 2016.
Tony Pulis led Middlesbrough to the Championship play-offs last season but they lost 1-0 on aggregate to Aston Villa in the semi-finals.