Birmingham City have a 15pc sell on clause with Jobe Bellingham, who is the subject of enquiries from Crystal Palace and Brentford.
The 18-year-old, the younger brother of Real Madrid icon Jude Bellingham, left the blue side of Birmingham for Sunderland last year.
But his old club will get a portion of the sale price if a Premier League club come in for him.
Southampton and Brentford are also keen on Sunderland's Jack Clarke.
The forward, 23, came through the youth ranks at Leeds United, but joined the Black Cats on a permanent deal in 2022 after a successful loan spell.
Bellingham and Clarke were part of the Sunderland side that finished 16th in the Championship last season, but both players have attracted interest from the top tier.
Sunderland's Jobe Bellingham has attracted interest from two Premier League clubs
Top-flight sides Southampton and Brentford are also keen on Sunderland's Jack Clarke