Damien Duff's move to Tottenham remains up in the air after Chelsea manager Jose Mourinho indicated just one more player would be leaving Stamford Bridge this summer.

And with Asier del Horno the likely candidate to depart, Duff's touted move across London is now in doubt.

Mourinho has targeted just one more signing and clearly wants to add a world class full-back to his squad with Juventus'
Gianluca Zambrotta and Ashley Cole of Arsenal at the top of his shopping list.

Del Horno is set to depart Stamford Bridge and Mourinho, who has already made successful raids for Michael Ballack and Andriy Shevchenko, insists that will be the end of Chelsea's summer transfer activity.

"I don't think there will be big movement. We can have one player to arrive and one to leave," he told Chelsea TV "I think other teams will work more than us on transfers. We have kept all the good players who were important for us last year and we have some new ones with a lot of quality."

Duff is due to enter talks regarding his future this week and tellingly, Mourinho's comment that only one player - del Horno - will be leaving during the transfer window suggests Duff remains in his plans.

Mourinho's chances of bringing a swift resolution to his search for a new full-back look remote with complications surrounding both Zambrotta and Cole.

Zambrotta is certain to depart Juventus, relegated to Serie B as punishment for their role in the Italian match-fixing scandal, but wants to remain in Italy.

Arsenal are in no mood to let Cole go with Wenger reminding Chelsea at the weekend the Gunners have resisted approaches for their best players in the past.

Both Patrick Vieira and Thierry Henry were kept despite the best efforts of foreign giants, with Vieira eventually being sold on the Highbury clubs terms, and Wenger sees Cole as another hugely influential figure at the club.

One certainty in Chelsea's summer plans, however, remains the departure of Del Horno.

The 25-year-old Spanish left back is being tracked by Valencia and his former club Athletic Bilbao, who joined the race for his signature today.

"We are ready to equal the €7million made by Valencia to Chelsea for Asier del Horno," Bilbao president Fernando Lamikiz told television station Bilbovision. "Then we would have to analyse the player's salary and negotiate with him."

Del Horno spoke earlier today about Valencia's interest, admitting his desire to return to Spain after a disappointing season in the Premiership.

"I would love to go back to the Primera Liga because it's a competition that I am very familiar with," he told Valencia newspaper Las Provincias.

"I am very honoured by the interest from Valencia. For the time being, though, my club is Chelsea and for that reason I have gone to pre-season training with them."

Chelsea returned for pre-season training yesterday but their World Cup stars will be back over the next two weeks.