Several Premier League clubs are also keeping tabs, as the England international continues to struggle for game time under new manager Ruben Amorim.
Mainoo, who started England's Euro 2024 final defeat to Spain and scored in last year's FA Cup final triumph over Manchester City, has yet to feature in United's opening two Premier League matches this season.
Once seen as a first-choice option, his role has shifted to that of a substitute since returning from injury in December. Sources suggest he does not comfortably fit into Amorim's preferred 3-4-3 system.
While reports in Spain have floated the possibility of a season-long loan move before the transfer window closes on Monday, United are unlikely to sanction such a deal.
The club are not actively looking to sell him and, with only four recognised central midfielders in the squad, would prefer to keep him. If anything were to materialise, a permanent transfer would be the more likely route.
Mainoo himself remains open to staying at Old Trafford but is determined to secure first-team football, ideally at a club competing in the Champions League. Talks over a new contract have stalled, adding to the uncertainty.
Tottenham Hotspur have made initial contact with Manchester United over a potential move for midfielder Kobbie Mainoo before the transfer window slams shut on September 1, sources have revealed.
Manchester United and Real Betis are racing against the clock to finalize a transfer for Brazilian winger Antony before the transfer window slams shut on September 1, according to reliable sources.
The ongoing contract dispute between Real Madrid and their star winger Vinicius Junior has hit a critical point, with both sides digging in their heels.
Bayer Leverkusen have landed a major coup by securing the signature of former Real Madrid star Lucas Vazquez on a free transfer, with the versatile Spaniard set to bolster their squad for the 2025-26 season.
