Chumi - Barcelona
Promoting one of their top academy prospects in the form of Chumi is the easiest and cheapest option for Ernesto Valverde's side. Still just 19, Chumi has plenty of developing to do still, but his ascension would mean that the Catalans could keep their powder dry and their money in their pockets in Janaury.
Branislav Ivanovic - Zenit
Very much an experienced campaigner, Ivanovic has been there and done it during a lengthy top-flight career which included a nine-year spell at Chelsea. A whole-heated leader, the Serb would certainly be a solid, dependable and fairly low-cost option.
Djené Dakonam - Getafe
A fast and athletic defender, the 26-year-old is a vital part of Getafe's squad. Very comfortable with the ball at his feet, he is also able to play in the middle of midfield, potentially offering Barcelona versatility as well as quality.
Andreas Christensen - Chelsea
Thought to be Valverde's favoured option, the 22-year-old is considered to be potentially one of the best central defenders in the world, but having not played a single minute of Premier League football this season under Maurizio Sarri he could be looking for a change of scenery. An excellent passer of the ball and comfortable in a back three or back four, the Dane would be an excellent, if expensive, opt