Celtic have slapped a £30million price tag on Kieran Tierney amid speculation linking the defender with a move to the Premier League.
The 20-year-old has developed into a key player for Celtic since breaking into the team in 2014 and Manchester United and Tottenham are among the clubs monitoring his situation.
Jose Mourinho is expected to sign a left back in the summer after losing patience with Luke Shaw, who has endured another frustrating season at Old Trafford.
But Scottish champions Celtic have no immediate plans to sell Tierney and the Daily Mail say it will take a Scottish record fee of £30m to strike a deal.
Tierney, a lifelong Celtic fan, signed a new six-year deal at the club last season and said last month: Im not thinking of anyone other than Celtic just now.
Im enjoying my career here. Ive just signed a six-year deal, so if that doesnt say long-term I dont know what does.
Tierney, who turns 21 next month, has already earned nine international caps with Scotland. He was named the Young Player of the Year by PFA Scotland earlier in the month.
It is claimed Europa League champions Atletico Madrid have also expressed interest in signing Tierney and plan to send scouts to Saturdays Scottish Cup clash against Motherwell to track his progress.
Last month, Tierney was tipped to thrive at a club like Manchester United by former striker Chris Sutton.
One thing that stands out straight away with Kieran Tierney is his personality, Sutton said. Hes only 20, but has already captained Scotland.
Hes level-headed, hard-working and very likeable. And hes a grafter, someone who works hard for the team.
It doesnt surprise me Manchester United are after him. Hes a Jose Mourinho-type player.
He really caught the eye in Europe last season and, amazingly, only Sporting Lisbon goalkeeper Rui Patricio has played more minutes in any top division across the world this season.
Hes extremely solid in defence, makes good decisions and can play anywhere across the backline.