But his future with PSG looks unclear, with the robust defender now in the final three months of his contract.
It is thought that he is ready to stay at the Parc des Princes, yet the Ligue 1 champions are reluctant to offer him a lengthy deal as they plan their own transfer activity.
This has alerted David Moyes, who is known to be in the market for a new centre-back, with Nemanja Vidic set to join Inter Milan this summer.
The Scot was so short of options yesterday at West Ham that he was forced to play Michael Carrick in the role.
Alex, 31, could be a wise addition, with both Phil Jones and Chris Smalling still inexperienced at the top level.
However United could face competition from sides in Italy, with Roma thought to be monitoring the situation.