The 23-year-old left-back spent last season on loan at Sevilla and helped the club win the Europa League.
But despite his impressive performances for Sevilla, Real Madrid are looking to offload Reguilon in order to free up space in their squad and bolster their transfer budget.
Reguilon was on Chelsea’s shortlist this summer as Frank Lampard wanted to sign a new left-back but the club succeeded in landing their first-choice target Ben Chilwell from Leicester City.
But according to Fabrizio Romano, Reguilon could still be heading to the Premier League as Madrid have made United aware that the player is available this summer.
Reguilon, who is currently in Spain’s squad alongside United goalkeeper David De Gea, is valued at around £18m by Madrid and is allowed the leave the club as Zinedine Zidane favours Marcelo and Ferland Mendy as his left-back options.
United have not yet made a decision over a move for Reguilon but the Madrid defender would provide strong competition for Luke Shaw, who missed the end of the season last month due to an ankle injury.
Brandon Williams was also forced to pull out of England’s Under-21s squad last week due to a foot injury.
United are aiming to lower Dortmund’s £108m asking price, and have still yet to reach a final agreement with Sancho and his representatives.
United have also cooled their interest in Jack Grealish as Aston Villa are demanding £75m for their captain.