Skysports.com understands that a number of Championship clubs are tracking Oxford defender Harry Worley.
The former Chelsea youngster dropped down to League Two last summer after being released by Leicester, but he quickly restored his reputation with a string of impressive performances for the U's.
Such was Worley's form that the 22-year-old was named Oxford's young player of the year after making a total of 46 appearances in all competitions.
Millwall and Bristol City are heading the list of potential suitors who are keeping tabs on Worley, who has two years left on his contract.
Worley failed to make a first-team appearance for Chelsea before joining Leicester in 2008.
But he failed to earn a first-team appearance with the Foxes too and was loaned out to Luton and Crewe before joining Oxford last summer.