#3 Iñigo Martínez (Real Sociedad)
The Spanish defender is the heart of the Real Sociedad defence and his composure on the ball allows them to play a high defensive line and control games by dictating play in the opposition half.
His experience with this style of play means he would fit into City's defence because they play in a similar manner. Although, their expert use of counter-pressing reduces the danger of counter-attacks and means the defence isn't left exposed, which is an issue at Martínez's current club: Real Sociedad.
Martínez was linked with Barcelona in the summer due to him having a £28m release clause in his contract. The deal never materialized for whatever reason, but it gives City a chance to pick up a bargain. He would certainly boost the depth in the centre-back area and could effectively take Vincent Kompany's place in the team due to the Belgian's injury issues.
The only issue is whether he would be happy being a backup because he is unlikely to take John Stones or Nicolás Otamendi's place in the team.
He would be substituting guaranteed first-team football for a realistic chance of winning trophies. It depends on what he prefers but he could work his way into the first-team because Guardiola has shown that competition for places is welcomed.
He may wait until the summer before leaving, though, because he needs first-team football to assert his claim for a World Cup place due to the amount of competition in the Spanish national team.