Mike McCarthy, Head coach of the Green Bay Packers seemingly coined this phrase on 12/30/2010 when asked if his team would have a tendency to let down if the Bears decided to rest their players in the season finale vs. the Packers. He answered the question with ... "That's a "polluted mindset".
When you let a lot of outside influences enter your way of thinking it can create a "polluted mindset". Our football team is very excited to play. It's important for us to clearly stay focused on winning and playing the best that we possibly can for the whole game. It's as simple as that."