Jose Mourinho has sanctioned Tottenham's attempt to re-sign Gareth Bale, despite being warned by former Real Madrid associates that the 31-year-old will struggle to meet expectations in the Premier League, sources have told ESPN.

As reported by ESPN on Tuesday, Spurs have moved ahead of Manchester United in the race to sign Bale, who has been told he can leave Madrid, either on loan or for a £18 million transfer, after falling out of favour with coach Zinedine Zidane.

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United have expressed an interest in the Wales international, but any move for Bale depends on the outcome of their pursuit of Borussia Dortmund winger Jadon Sancho, which remains at an impasse.

With Spurs being able to offer Bale the certainty of a move and the chance to play first-team football, the player now favours a return to the club he left for Madrid in an £85.3m deal in Aug 2013 and talks began earlier this week to strike a deal.

Spurs manager Mourinho, who attempted to sign Bale during his two-and-a-half-year spell in charge of United, is fully supportive of the move for the four-time Champions League winner, believing he can provide the attacking quality required to ease the goal scoring burden on Harry Kane.

But having forged strong relationships with key staff during his spell as Madrid manager between 2010 and 2013, Mourinho has spoken to former colleagues at the club to find out why Bale has fallen out of favour under Zidane.

Sources have told ESPN that Mourinho has been urged to proceed with caution on Bale, who has been troubled by injuries in recent seasons. But despite the negative feedback, the Spurs boss believes that the player can be revitalised by a return to north London.

With United unable to offer Bale a swift move to Old Trafford, Spurs could move quickly enough to secure a deal in time for Bale to be involved in the squad for Sunday's league clash against former club Southampton.