Manchester United fear they are losing the battle to hold on to Marouane Fellaini

Manchester United are bracing themselves for a midfield overhaul in the summer after failing to agree a new deal with Marouane Fellaini.

The Red Devils midfielder is out of contract in the summer and is yet to agree a new deal with the club. He is permitted to hold talks with interested parties and agree a pre-contract with a view to a free transfer in the summer.

Fellaini joined the 20-time English champions from Everton in 2013 following the arrival of David Moyes as Sir Alex Ferguson's departure. The Belgian midfielder struggled to impose himself under Moyes or his successor Louis van Gaal and was regularly made the scapegoat when United underperformed.

Jose Mourinho's arrival in the summer of 2016 saw his fortunes change as he became one of the Portuguese coach's key players. He was used in his primary position as a midfielder, but also at time's as a secondary forward when they were chasing the game.

According to the Mirror, the United hierarchy are increasingly fearing that Fellaini will not extend his deal with the club and will leave on a free transfer at the end of the season. The Belgian is currently sidelined with a knee injury and is not expected to return to action for at least another month.

Despite not being a regular, Mourinho holds Fellaini in high regard and is keen for the midfielder to extend his deal with the club. However, the Belgium international has hinted that he could leave after admitting that he has at times been treated as a criminal for his aggressive style of play.

Fellaini will not be short of suitors should he decide to leave the club with Paris Saint-Germain and Besiktas among the clubs pursuing his signature. The 30-year-old's departure will leave a massive hole in Mourinho's midfield, as he is not the only midfield departure expected this summer.

Michael Carrick is also set to hang up his boots at the end of the campaign with the England international expected to join Mourinho's coaching staff ahead of the 2018/19 campaign. The Portuguese coach has already confirmed that strengthening the midfield will be a major priority in the summer.

According to the Daily Mail, the Red Devils have identified a number of targets to fill the void left by the potential departure of Fellaini and Carrick's move to join the backroom staff. The manager is said to be keen to find a player that can fit in alongside Nemanja Matic and Paul Pogba.

Nice's Jean Michael Seri, Lazio's Sergej Milinkovic-Savic, Real Madrid maestro Toni Kroos, Victor Wanyama from Tottenham Hotspur, Serie A leaders Napoli's Jorginho and Chelsea schemer Willian are said to be the list of players United could target in the summer.