The Red Devils shunned the opportunity to re-sign Cristiano Ronaldo in favour of pursuing a deal for Bale.
The Welshman is considering his future at the Bernabeu and revealed after Madrids win against Liverpool in the Champions League final that he would decide this summer whether or not to quit the club.
United have long tracked Bale and the Manchester Evening News claims the Red Devils have advanced talks with the Welshman in recent weeks.
The 28-year-old fell out of favour under Zinedine Zidane but Uniteds chances of signing Bale were damaged when the Frenchman left the club at the end of the season.
Nevertheless Julen Lopeteguis appointment has failed to convince Bale that he has a future in Spain and he wants to speak to the Spaniard to clarify his position at the club.
More: Manchester United FC
Jose Mourinho spoke to Bale after Uniteds friendly with Madrid during the clubs pre-season tour to the United States in 2017 and said how can I buy you if you dont speak to me?.
The Portuguese boss has made no secret of his desire to sign Bale and the next fortnight is likely to prove pivotal to the clubs chances of signing the former Spurs man.