Maguire included in England squad despite trial in Greece
the Nations League finals last June.
City team-mate John Stones has been left out of the squad, but Raheem Sterling got the the nod despite questions over his availability.
There is no place for Callum Hudson-Odoi, Fikayo Tomori, Danny Rose and Callum Wilson having been in the squad to face Kosovo in
November, while Ross Barkley and Fabian Delph are also conspicuous by their absence.
Jordan Henderson, Alex Oxlade-Chamberlain, Ben Chilwell and James Maddison miss out through injury.
Southgate accepted it was a difficult decision over Maguire.
“Yes it is clearly a decision that is not straightforward and a decision that in the end I could only take on the information I have,” the England manager told a press conference.
“I have spoken with Harry, I have the insight to the story which is very different to what is being reported.
"You can only make decisions on facts you are aware of.
“If facts or information changes I will have to review that decision, but I have a fantastic relationship with the boy, he has been a fantastic character for us – he has my support at this moment.
“I’m not going to get into hypotheticals of what might happen, but I have got to reserve the right to review if further information becomes available.
“You always make decisions to the best of your ability given the information you have.
"People may agree or disagree with those decisions, but it is a position where every manger finds himself.
“Harry regrets the fact he has brought that sort of focus and attention to the team – he apologised for that – but also has his own side of the story.”