Barça's other centre back candidates

Apart from David Luiz, three other names are being considered for the centre back spot at Barcelona. Vermaelen, who currently plays for Arsenal; Mangala, a renowned centre back who is set to leave Porto in the summer; and a familiar face in La Liga, Íñigo Martínez, who is being pursued by clubs such as Real Madrid.
Vermaelen is one of the players who has been linked to Barcelona since it embarked on the search for a centre back two seasons ago. Since then, the club has remained interested in this Gunners player and the club's technical department likes him a lot. Aged 28, the Arsenal and Belgium captain is an experienced player. A few days ago he announced that he does not wish to leave his club.
Mangala is one of the most renowned defenders in world football. At the age of just 22, several teams are following him, Barcelona being one of them. Porto will definitely be selling the player at the end of the season and he will not be easy to pick up given the large number of interested parties. The player's release clause is €50 million, although he could be sold for less than this.
Íñigo Martínez is another of the names that has been linked to Barcelona for some time. He was a player who Guardiola liked a lot and his name has been cropping up since Barclelona started looking for a centre back two years ago. He would likely cost somewhere in the region of €30 million. Íñigo's big advantage over the other candidates is his great familiarity with the Spanish Liga.