Everton, West Ham and Leicester are among the clubs interested in signing Middlesbrough captain Ben Gibson this summer.
The Middlesbrough academy graduate, who is the nephew of Boro owner Steve Gibson, was called up to the England squad by Gareth Southgate last season.
Gibson could yet stay at Boro if they gain promotion back to the Premier League, however the Premier League trio are monitoring the situation.
The defender, who penned a new five-year deal at the Riverside Stadium earlier this season, is valued at around £20m.
Leicester made an approach for Gibson in the last two windows, and a centre back is still top of their summer wanted list.
Gibson has played every minute of Middlesbrough's games in the Championship this season. Boro are fifth in the table and host fellow play-off hopefuls Millwall, live on Sky Sports Football on Saturday.