Southampton have identified Real Valladolid defender Mohammed Salisu as a January target.
Saints are one of a number of clubs to scout the 20-year-old this season.
The centre-back has a release clause of £10.2m, per Sky Sports.
Despite their interest, manager Ralph Hasenhuttl has prioritised finding new fullbacks.
Hasenhuttl has looked Genk right-back Joakim Maehle and Spurs' Kyle Walker-Peters.dz