The idea that you can tell the press a player hasn't been training well and then demand the player in no way challenges that claim is daft. It's totally different to the Ronaldo situation where he openly criticised the club and other players.
It's not uncommon that players are mentioned in a somewhat negative way in public by the manager, far from it. Players
challenging it in public however is extremely rare, for obvious reasons..Players are expected to accept it and get on with it, no matter how much they disagree with the reasoning, which is what they normally do, they fall in line and accept that their managers word is law and then they get on with it. Just snubbing a managers hand when coming off as a substitute, or heading straight into the dressing room instead of sitting down on the bench, is a no no that needs to be dealt with, as it can easily be seen as the player challenging the manager. It's not an open invitation..
There's also the bit about being professional and having enough self awareness to see where you are and what your role actually is. Even if the player is right, he is actually being treated unfairly, it's still nothing new and especially not at a football club. Plenty of times you have managers signing someone, they get sacked and whoever comes in next doesn't want that player. It's a way of life and they get on with it. Sancho going public and claiming he's a scapegoat and the manager is lying about his reasons also reflects negative on Sancho's character, and it's a pretty clear way of challenging the authority of the manager and as a manager you can't tolerate that in any way. I doubt anyone at the club would've been bothered if Sancho had stuck to disagreeing with the reasoning and then made a generic statement about how he will continue to prove himself for the manager and be available for when he's needed.
Common sense and a bit of professionalism and Sancho just gets on with it, he can consider his options towards the summer if the manager is still at the club and that's it. No problems for him, no problems for the club, no problems finding a new club. He can open up about his troubles in an interview later on, like most other players do. I just don't understand why anyone wants characters like this at the club. He's an extremely expensive player, both in terms of wages and the transfer fee, yet he's failed to deliver even close to expectations and at the same time he's gaming online into the early hours of the morning and struggles with his discipline. He'll be 24 in a few months, age isn't an excuse any longer.