Chelsea are keen on bringing Spanish fullback Oscar De Marcos to Stamford Bridge in a bid to strengthen their defensive ranks.

With regard to defensive reinforcements, Chelsea’s transfer window can’t be labelled as a complete failure after the acquisition of Marcos Alonso and David Luiz, but the effects of not getting their top targets are evident. Cahill and Ivanovic haven’t shaken off last season’s slump, and with Kurt Zouma and John Terry injured, the Blues’ leaky defence has cost them dearly and they failed to register a win in the month of September.

BILBAO, SPAIN - AUGUST 30: Oscar De Marcos of Athletic Club Bilbao?controls the ball during the La Liga match between Athletic Club and Levante UD at San Mames Stadium on August 30, 2014 in Bilbao, Spain. (Photo by Juan Manuel Serrano Arce/Getty Images)

BILBAO, SPAIN – AUGUST 30: Oscar De Marcos of Athletic Club Bilbao?controls the ball during the La Liga match between Athletic Club and Levante UD at San Mames Stadium on August 30, 2014 in Bilbao, Spain. (Photo by Juan Manuel Serrano Arce/Getty Images)

According to Spanish publication El Desmarque, Chelsea have shown an interest in Spanish fullback Oscar De Marcos, who currently plies his trade for Athletic Bilbao in the La Liga. The report states that Chelsea had got in touch with his father a few days ago via an intermediary in a bid to try and open talks about a possible move to Stamford Bridge.

Chelsea are reportedly willing to offer the 27-year-old a 4-year-deal and double his current wages. Marcos also has a release clause of €40 million in his current contract which runs until June 2019.

While that fee shouldn’t pose too big a problem for the Blues, it remains to be seen whether that amount of money would be enough to prise Marcos away from the San Mames, given his fierce loyalty to the Basque club.

Since making his debut for Los Leones in 2009, he has gone on to play nearly 300 matches for the club in all competitions, but is yet to make his full international debut for his country, despite being called up to the Spain squad. At 27 years of age and a considerable amount of experience under his belt, it remains to be seen whether Chelsea would actually be willing to spend 40 million euros on a player who has very little European experience and no international experience for his country.