Manchester United are seeking a deal for Celtic full-back Kieran Tierney with Jose Mourinho in the market for a new left-back, especially with Luke Shaw's future at the club seemingly uncertain. The Red Devils are looking to challenge for the title next season and with Champions League football on the horizon, the Portuguese manager is keen to strengthen his defence.

The Mirror reports that Arsenal are also interested in the defender, who is expected to set their suitors back by a fee in the range of £15m ($19m). The Scotland international is highly regarded in the market and United have been regularly sending scouts to keep an eye on the defender over the course of last season.

Arsene Wenger is a big admirer of the left-sided defender and is keen to bring him to Arsenal in the summer as uncertainty surrounds the future of Kieran Gibbs, who will have just one year on his contract at the end of the season. However, the north London club have already signed Sead Kolasinac on a free transfer and with Nacho Monreal going in at full tilt, they may see their interest wane, allowing other parties to make a swoop.

The defender earned a lot of plaudits for his performance against England in a 2-2 draw but the Scottish Champions want him to stay for at least another year. The fact that he has four years left on his deal will make it even more difficult to prise him away.

The 19-year-old has established himself as a regular in the Celtic side under Brendan Rodgers and played a key role in helping them retain the Scottish Premiership this season. Tierney made 36 appearances in all competitions and contributed with 12 assists showing that his attacking prowess is as good as his defensive ability.

Chelsea and Tottenham Hotspur have also been linked with a move for the player but according to the Manchester Evening News, the Red Devils will hold a slight advantage over their Premier League rivals as the defender is said to prefer a move to Old Trafford over his other suitors. Celtic are, however, not too keen to sell one of their brightest prospects who has been nominated for the Scottish PFA young Player of the Year award.