Manchester United has reportedly identified French defender Eliaquim Mangala as the ideal replacement for Rio Ferdinand, who will be leaving Old Trafford at the end of the season.
However, Portuguese side Porto wants £35 million for their powerful centre-half, whose contract expires in the summer.
According to the Mirror, Moyes also faces the threat of losing club captain Nemanja Vidic, who is out of contract in the summer - emphasising the importance of signing a top class centre-back, with Manchester City already failing in a double £50 million deadline day bid for Mangala and Brazilian defensive midfielder Fernando.
The report mentioned that although Manchester City could now pursue alternatives to Fernando, whose Porto contract expires in the summer, it is understood that Mangala will remain a priority target.
City have monitored Mangala for more than 12 months, with boss Manuel Pellegrini regarding the player as the ideal partner for captain Vincent Kompany at centre-half, the report added.
Image: Eliaquim Mangala
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