On a chaotic evening, United's official photographer has arrived at the AON Training Complex as the club doctor has left it.
Both moves seem significant given Marouane Fellaini has apparently handed in a transfer request at Everton as they could allow the doctor to oversee a medical before heading back with the Belgian for his official confirmation as a United player.
Herrera remains in Bilbao though.
Reports in Spain have suggested United have agreed to meet a 36million euro clause in the midfielder's contract and have also agreed a five-year deal for Herrera.
However, whilst club officials visited La Liga headquarters this evening in order to conclude the paperwork, they apparently hit an unexpected snag and left without completing the deal.
With time ticking down to the transfer window closing, United may have a problem pushing through the deal.
What they do have though is a little bit of wriggle room afforded to clubs who have a transfer agreement in principle without actually finalising it.
Under such circumstances, providing the Premier League receive a Deal Sheet at some point between 9pm and 11pm BST this evening, containing signatures from both clubs and the player, United will be granted an additional hour to complete the transfer.
In that time, all loose ends must be completed to comply with FIFA's international transfer matching system to allow the deal to be ratified.
As it is virtually unknown for the world governing body to extend the time limit for these transfers beyond midnight, if United have not finalised the paperwork by that time, they will have to walk away from what would be the second biggest incoming transfer in their history.
It seems strange for United to find themselves in such a tight spot so close to the deadline.
And the fact reports have also emerged of a Euro40million bid for Real Madrid midfielder Sami Khedira, which has been rejected by the Spanish giants, just adds an even more surreal air to the evening.
For whilst Dimitar Berbatov famously arrived from Tottenham with minutes to spare before the transfer window closed in 2008, in more recent years United have been able to get all their transfer business done early and leave the deadline-day crush to others.
Questions will certainly be asked of the approach that has been taken by Moyes and executive vice-chairman Ed Woodward, although the fact both men are so new into their jobs is probably one of the major reasons why the situation has ended the way it has.
Moyes' desire to be reunited with Fellaini has been well established for some considerable time.
His interest in Herrera is far more recent.
The 24-year-old played twice against United in 2012 as part of the Bilbao side that was so impressive in dumping them out of the Europa League, scoring at Old Trafford.
Although the 24-year-old's two goals in 63 La Liga appearances is not that impressive, David Moyes feels Herrera can add the drive to his midfield which was notably absent during yesterday's 1-0 defeat at Liverpool.
At present exchange rates, the transfer would cost £30.53million, just less than the club record £30.75million United paid for Dimitar Berbatov in 2008.
It is also thought the transfer will include a commitment from United to play a friendly at Bilbao's new San Mames stadium in 2015.
United have however agreed a deal to loan young midfielder Nick Powell to Wigan, which in turn could free James McCarthy to join Everton, and therefore make Fellaini's move more likely.
"We obviously had Tom Cleverley on loan and I think United were happy with the job we did with him, so it's good news that we've got the lad," Whelan told BBC Sport.
"We've done the deal for a season long loan."