United waiting to wrap up Mata move
United have been unable to sign off the transfer as quickly as initially intended due to the red tape involved in Chelsea's capture of Basle midfielder Mohamed Salah.
As they would have preferred the deal to be completed before sending Mata for a medical, the Spain star has been unable to link up with the United squad.
Now the club must decide whether to change that stance and instead send Mata for a medical over the weekend, which would allow him to train on Sunday and Monday ahead of the Cardiff encounter.
Even with the temporary delay, United still see no reason why Mata would not be involved against Ole Gunnar Solskjaer's men, as the long process of trying to recover their status begins.
Speaking on Friday lunchtime, Chelsea manager Jose Mourinho suggested he was flexible in his approach to the transfer, which means United should not encounter a problem if they opt to give Mata his medical and get him on the training ground before the formalities were complete.
"It's what he wants," said Mourinho.
"It's what he asked us to accept. Chelsea Football Club is proud to act this way, in an open way, in a human way.
"It's good for Juan, it's good for the Premier League and the offer in financial terms is the right offer.
"The offer, compared with what the club paid two years ago (when Mata signed from Valencia), was fantastic.
"If Man United pays their record for a player it's because they know exactly what they want.
"They are convinced he's going to be important for them and we hope that he does very well for them. No fears at all. We are convinced he's going to do well."
United boss David Moyes will hope Mata's arrival will galvanise a team that endured its lowest moment on Wednesday, when they failed to navigate a Capital One Cup semi-final against lowly Sunderland.
That they then lost what many claim to be the worst penalty shoot-out ever only increased the air of gloom.
It is patently obvious however, that Mata's eventual arrival can only be the start of a lengthy rebuilding process, with the centre of midfield - from which Michael Carrick is now likely to be absent with an ankle injury sustained in midweek - believed to be the main priority.
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