I don't get how a minor incident like that involving one of the country's top talents is not handled quietly/privately, including any disciplinary actions.
My take on it is, they probably heard that the press had the story and wanted a comment on it. So they decided to get ahead of it.
Once upon time, minor incidents would be kept quiet, but that is a lifetime ago. But then you have the English media
All it needs is someone who was there, to relay the story to a friend and then that person sells it. It's England's best player headlocking a squad player, that's a big story. Especially after last month, with Maddison getting caught in the Casino the day after he was released because he was ill. Southgate's authority was being undermined (everything is going well with the team, but 2 camps with b2b incidents, ngl tbh), unfortunately for Sterling, he was the one who did the next incident.
Knowing the English press, they would of gotten hold of the story and put it out there on Thursday, the day of the game. And then everything would of been about the incident. Now it makes what happened even bigger than it is now and with the intense media, how can Southgate play Sterling if the story is out on Thursday. If Southgate plays him, people will say, he was rewarding Sterling's behaviour.
Southgate even said, if it was unwraps and people see Sterling not in the match day squad, people are going to ask questions, about why isn't he picked, when he is the most inform player in the country. With the press camped at St George's Park, they will find out the story one way or another. Sterling trains all week and then doesn't get picked, the media will make up their own story.
