Everton's Brendan Galloway is the latest left-back to have been linked with a January switch to Manchester United.
Luke Shaw started the campaign as Louis van Gaal's number one option in that position, but the England international is not expected to feature again this season due to the double leg break that he sustained against PSV Eindhoven last month.
A host of left-sided defenders, including Jetro Willems, Morgan Fox and Charlie Taylor, are all said to have been monitored by Van Gaal as potential cover for the stricken Shaw.
However, according to The Mirror, Galloway's form for the Toffees this term has also captured the attention of the United boss and his coaching staff at Old Trafford, with a winter bid potentially in the offing.
The 19-year-old England youth international has deputised for Everton in the absence of the injured Leighton Baines.