Chelsea are one of the teams in the EPL who are very serious but the manager doesn't have the balls to admit it and I believe he has made the player to accept it that they're not in any way qualified to be title contenders. Is a shameful thing to say that a club you're managing are not yet in the title race even when you see how awesome you team have been doing even better than the current Champions and the league leaders. I think Enzo Maresca learnt a lesson from the other coaches who got fired, he noticed that the Chelsea club and the fans have this kind of pressure they inflict on every new manager to always take them to the top even when they know is not immediately it had to happen. Enzo is not really using mind game per say but he is avoiding being pressured and he also wants the players to play without pressure and he feels it will help them do well.
I disagree with your assessment on Chelsea. It could well be a tactical strategy by Enzo Maresca to shift the focus of his players towards gradual progress rather by been burdened by the pressure of been called title contenders. I think this approach allows the team to focus on their development and long term goals rather than short term results. By managing the expectations of the fans, Enzo Maresca ensures that his players are not overwhelmed by external pressure which can negatively impact their progress and performance.