David Moyes managed to pull off the shock of the month by signing Chelsea playmaker Juan Mata in a £37.1m deal, and whilst many left backs and central midfielders have been linked with moves to Old Trafford, it seems Moyes is looking to add another centre back to his ranks before the deadline.
Porto could be about to lose both of their starting centre halves, with Eliaquim Mangala interesting United's cross-city rivals Manchester City, but seem willing to let Otamendi leave the club after the Argentine international saw a proposed loan move to Valencia fall through earlier this week.
A £20m fee was suggested at that time, and Moyes is clearly hoping to grab himself a bargain with their £12.3m offer for the former Velez Sarsfield man. Otamendi displays a good reading of the game alongside decent pace and aerial ability, despite being only just over 6ft tall.
But with Otamendi's arrival possibly set for completion on Friday, where does this leave the other Manchester United centre backs – Nemanja Vidic, Rio Ferdinand, Jonny Evans, Phil Jones and Chris Smalling?
The move for Otamendi, who turns 26 in February, would suggest Moyes is making a commitment to getting younger along the backline. There have been plenty of rumours surrounding the futures of Vidic (32) and Ferdinand (35) recently, with both entering the final few months of their contracts. A move to sign Otamendi would almost certainly mean that United won't be keeping hold of both players, with Vidic the most likely to stay at the club.
Meanwhile, Moyes may continue to use either Jones or Smalling as right backs if Otamendi is landed. Rafael has been in and out of the team under the former Everton boss this season, but with no other right back signed his month and another centre back potentially on the way, it may spell out that Jones and Smalling will continue to fill in at full back until the summer, where United will hope to land another defender.
The move way also see Evans slip down the pecking order. The Northern Ireland international has usually been a bit-part player at Old Trafford, and that may be the case once again if Otamendi arrives at the club. Whether the former Sunderland loanee will see that as the end of his Manchester United career or more motivation to break back into the first team remains to be seen, but Evans has certainly improved his play over the last 18 months.
With some gap between what Porto want for Otamendi and what United have offered, the deal may take some haggling throughout deadline day, but it seems United and Moyes aren't done in the transfer market this month just yet.
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