Reading between the lines with Harris it sounds like another case of a manager not relishing the head coach role or wanting the reduced control over what were once core parts of his job. The below statement sounds very familiar.
Part of the club statement says "As we look forward the appointment of our next head coach will align with the clear strategy and vision previously laid out for the future of Millwall FC both on and off the pitch"
Harris was brought in to Millwall with the objective of saving them from relegation last season. I am not sure it was ever intended to be long term to be honest, it was an 18 month contract so he's roughly at the halfway point now.
Reading between the lines with Harris it sounds like another case of a manager not relishing the head coach role or wanting the reduced control over what were once core parts of his job. The below statement sounds very familiar.