Barcelona defender Thomas Vermaelen has confirmed that Everton were interested in a move for him in the summer transfer window, but he was forced to stay with the club. Ronald Koeman was interested in bolstering the Blues' defensive options over the summer, with the Belgian international fitting the bill of the left-sided centre-back the Dutchman was looking for. However, any advances from Everton to bring the former Arsenal man to Goodison Park were rebuffed by the Catalan giants, as they didn't want to be left short in their defensive options. Vermaelen told Belgian publication DH : “The board told me they needed four centre-backs. I didn’t have a choice but to stay. Clubs tried until the very last day, like Everton, but it was impossible. I wasn’t even able to negotiate.