Manchester United are reportedly considering a summer move for Celtic full-back Kieran Tierney.
The side have already added Victor Lindelof to their defence this summer, but questions remain over the left-back position, with Luke Shaw struggling to impress during the 2016-17 campaign.
Italian international Matteo Darmian finished last season as the club's first-choice left-back, although it is understood that head coach Jose Mourinho wants to improve that position ahead of a busy 2017-18 campaign.
According to the Daily Star, Man United scouts watched Tierney during Scotland's 2018 World Cup qualifier against England last weekend, and the Red Devils could launch a £15m offer over the next week.
The 20-year-old, who came through the youth system at Celtic, has scored three times in 75 first-team appearances for the Scottish giants since making his debut during the 2014-15 season.