La Liga champions Barcelona will test Chelsea's resolve to keep Brazilian defender David Luiz by offering a reported £29 million for him in the January transfer window. The Daily Star says reports in Spain indicate that Barca boss Gerardo "Tata" Martino remains keen on 26-year-old Luiz as he seeks a replacement for ageing skipper Carles Puyol at the Nou Camp. Luiz lost his place in the Blues XI under Jose Mourinho before picking up a knee injury, but is now back in full training. He has made just ten appearances for the Special One this season. With the World Cup coming up in his native Brazil this summer, Luiz will not want to be sat on the Chelsea bench behind Mourinho's preferred centre back pairing Gary Cahill and John Terry. Barcelona are understood to have been tracking Luiz for some time and hope that their offer will be accepted by the Blues. Martino also has former Manchester United man Gerard Pique, ex-Liverpool player Javier Mascherano and academy graduate Marc Bartra as defensive options at the Catalan giants. Chelsea and Barca complete their respective Champions League groups on Wednesday evening, both having already qualified for the knockout phase with games to spare.