Manchester City plan on signing a center back during the January transfer window.
Pep Guardiola is concerned City doesn't have enough depth at the position due to the fitness issues of Vincent Kompany.
City were close to completing a deal for West Bromwich Albion defender Jonny Evans in August and could return with a fresh bid.
Real Sociedad centre back Inigo Martinez has also been watched by City scouts while reports suggest they could be interested in Southampton's Netherlands international Virgil van Dijk.
Evans, Martinez and Van Dijk would all be eligible to play in the knockout stages of the Champions League.
