The leftback looked like he may have suffered another major injury minutes into the second half on Saturday, with his head appearing to hit Dani Carvajal's hip before sickeningly bouncing off the turf.
Saturday will be a key game for Manchester United as they seek to recover from a poor start to the season.
England's Luke Shaw (centre) receives treatment after picking up an injury Shaw's injury overshadowed what had been a somewhat chastening night for Southgate's side.
As soon as the impact occurred, the Real Madrid man went to check on the Manchester United full-back.
'All being well, he has a mandatory seven-day period that he has to serve with the concussion, but he should be back in the fold as soon as that's done'.
The left-back has started the season well, earning praise from boss Jose Mourinho for a number of impressive displays.
He has since tweeted that he is doing fine and will come back stronger.
Thankfully the prognosis was upbeat later as England's medical team confirmed that it was not as serious as the 81,000 fans inside Wembley Stadium had at first feared.
England and Spain players took to social media to send their support to Shaw, including his United teammates Marcus Rashford, Ashley Young and David de Gea.