Michael Keane is on Manchester United's radar ahead of Jose Mourinho's summer rebuild but they face the prospect of losing out to Liverpool, sources have told ESPN FC.
Keane has impressed enough for Burnley this season for Mourinho to ask United to monitor the defender's situation.
The 24-year-old, who made his England debut in March, is expected to leave Turf Moor at the end of the season, and United are in the running to bring back a player who left Old Trafford permanently in 2015.
However, they will have to beat any offer Liverpool make to secure a deal.
Sources have told ESPN FC that Keane will have to be convinced to return to the club he joined as a schoolboy after being left unhappy with the way his departure was handled by former boss Louis van Gaal.
It has given Liverpool the upper hand in a transfer battle that could yet include Manchester City and Everton.
However, Keane's links with Rio Ferdinand's New Era sports management company will give United hope of pipping Jurgen Klopp's side.
Ferdinand won six Premier League titles and the Champions League during 12 seasons at Old Trafford and in February the former England defender backed Keane to be successful if he does decide to return.
Mourinho has turned his attention to Keane after a season in which all of his senior centre-backs have suffered at least one injury lay-off.
Eric Bailly, Chris Smalling, Phil Jones and Marcos Rojo have all been sidelined. Keane, meanwhile, has only missed one game for Burnley this season, when he was rested for the EFL Cup defeat to Accrington in August.
Rojo is set to miss the rest of the season after undergoing surgery last week on the knee ligaments he damaged during the Europa League quarterfinal victory over Anderlecht.
Smalling and Jones have both missed the last seven games after picking up injuries in the last international break.
Smalling is nursing a knee injury while Jones has a toe problem and there has been speculation they could miss the rest of the season.
However, with Bailly and Daley Blind Mourinho's only fit senior centre-backs, the United manager suggested after the win over Burnley he would like Smalling and Jones to make themselves available for Thursday's derby with Manchester City for the good of a team that has been ravaged by injuries over the last month.
Mourinho also has youngsters Timothy Fosu-Mensah and Axel Tuanzebe available as centre-back options.
Zlatan Ibrahimovic and Juan Mata are also set to miss the rest of the season while Paul Pogba was forced off against Burnley and is a doubt to line up at the Etihad Stadium this week.