Juan Mata has fallen out of favour at Stamford Bridge, with returning manager Mourinho stating that the winger can leave the club, according to the Express.
Having made just 18 appearances this season, scoring twice, Mata has failed to break into the first team this season, despite his impressive season last year for the Blues which saw him top Chelsea's assist chart with 35, 17 of which came in the league.
With Mourinho favouring the Brazilian youngster Oscar, Mata will be looking to get away from Stamford Bridge in his attempt to make the plane to Brazil with the Spanish national squad.
Manchester United manager, David Moyes is reportedly interested in Mata, as he looks to bolster his heavily criticised midfield.
The playmaker would be an ideal signing for the Red Devils, giving them the creativity and drive that they currently lack in their midfield and after the Spaniard's angry reaction to being substituted in Chelsea's impressive 3-0 victory away to Southampton, Mourinho has said that he is open to bids for his midfielder.
The ex-Valencia star moved to the Premier League for £23.5million in 2011 and with the playmaker being at what would be his peak age, Moyes could be looking at this signing as one of his more expensive New Year purchases.
The expected departure of Luis Nani however, will add money to Moyes' transfer funds, where Mata would likely replace the Portuguese winger at Old Trafford, who looks like he will be moving to Italian giants, Juventus.