Fears are growing for Vertonghen's future at White Hart Lane after the defender hinted he could leave should Spurs fail to qualify for the Champions League. Vertonghen is on a list of names being considered by Barcelona to replace Carles Puyol, who announced this week he will leave the Nou Camp at the end of the season. Chelsea's David Luiz, Arsenal defender Thomas Vermaelen and Liverpool's Daniel Agger have also been mentioned as possible targets for the Spanish giants. But Tottenham are already drawing up contingency plans in case they go for Vertonghen, with sources close to Mathieu insisting he is top of the north London club's summer wish list. The 30-year-old France international is a centre-half who can also play at left back and Spurs have had him watched in La Liga several times this season.