No one is stopping any player from going in and asking to be released from their contract or traded because they aren’t happy with the organization or because they would rather be free to sign with another team.
Yet the fact is it is up to the organization to agree to let the player out of his contract. If the Texans decide that they don’t want to let Watson out of his contract or trade him. Watson can either play under the terms of his contract or sit out and not get paid.
It is not unusual for teams to let older veterans out of their contracts near the end of their careers so they can go somewhere else. It also opens up a lot more cap space when the high priced veterans are cut or traded. Yet I can’t ever remember when a team agreed to trade a franchise QB when he had four years left on his contract simply because he now wants to be traded.
Watson can certainly request to be traded but the Texans can also deny his request.