Rightly or wrongly the Euros left a slightly bitter taste for me.
I reckon him going was more down to Southgate being desperate because he had no other left backs. I dont blame him at all for that as why shouldn't he want to be there if he's picked? But the guy contributed nothing to last season, had a moan on at least one occasion about fans questioning his commitment, then mysteriously gets himself fit enough to play for a couple of England games. Now he isn't fit again.
There were a lot of noises towards the end of last season about it being suspected certain players were more concerned with saving themselves for the Euros than coming back into a struggling United side, so it's really not a good look.
And assuming it is just legitimate bad luck (I thought he looked miles off the pace for England tbh), he's injured or miles off his best a majority of the time. When he's good he's extremely good but City, Arsenal, Liverpool and any consistent team don't rely on players who are persistently good one year and bad/injured the next.