TVE reported on Monday that the Portuguese side coached by Spaniard Julen Lopetegui have bid for Casillas and the Spain captain is giving the offer serious consideration.

Both De Gea and Real Manager Rafa Benitez are keen to have Casillas at another club before the start of next season so the controversy over who plays in goal at the Santiago Bernabeu does not overshadow the season as has happened in the last three campaigns.

TVE, who reported the offer, also reported last month that Real Madrid are willing to ensure Casillas earns the same at his new club over the next two seasons as he would have earned by staying at Madrid until the end of his contract in 2017. 

This would be done by paying the difference between the £3.9million salary he earns at Madrid and what his new club are prepared to pay him.

Lopetugui already has six Spaniards in his squad and both his assistant coaches are Spanish. If Casillas completes the move he could even face Real Madrid in next season's Champions League.

(dailymail.co.uk)