Bristol City defender Aden Flint is undergoing a medical with Middlesbrough.
Boro will pay around £7m for the 28-year-old if the deal goes through, according to Sky Sports News.
Flint was a sought-after defender this summer, with West Bromwich Albion and Fulham among the clubs to have been linked with him.
The centre-back, who cost the Robins just £300,000, has spent the last five years at Ashton Gate, scoring 37 goals in 246 appearances in all competitions.
Meanwhile, Sunderland’s Paddy McNair is also said to have undergone a medical at Boro this week.