Sevilla are reportedly fearful that Manchester United are ready to trigger the £69m release clause in defender Jules Kounde's contract.
The 22-year-old has been one of the most coveted centre-backs in the world in recent times after impressing for Sevilla since joining in July 2019.
A number of European heavyweights have made their interest known, with Chelsea already having a £42.5m bid knocked back in the summer window.
Sevilla remain reluctant to sell the five-cap France international at any price, but clubs are aware of Kounde's buyout clause.
According to AS, the La Liga side are worried United are prepared to spend big on Kounde in the January window as they look to further strengthen their defence.
Ole Gunnar Solskjaer has shifted to a three-man defence over the past few weeks and is supposedly looking to partner Kounde with Harry Maguire and Raphael Varane.
United have conceded 17 goals in 11 Premier League games this season - only six sides have let in more.