Middlesbrough are becoming frustrated with Tottenham regarding a transfer for Djed Spence.
The right-back, who spent last season on loan at Nottingham Forest, is in demand this summer.
According to Football League World, Spurs are stalling on concluding a deal for Spence.
Boro are concerned about the protracted nature of talks, which is giving Nottingham Forest a chance to make another move for Spence as well.
The 21-year-old played 42 games for Forest as they gained promotion to the Premier League through the Championship and playoffs last season.
He is a key target for Spurs boss Antonio Conte, but talks have still not progressed to an advanced stage.