As if adapting to life in a new division was not hard enough, Colchester United must now do so on the back of another managerial departure.

Kevin Keen’s surprise exit has left the U’s searching for a third permanent managerial appointment in the space of less than two years.

His 127-day reign in the Weston Homes Community Stadium hot seat is the second shortest for a contracted full-time Colchester manager.

Now Keen’s brief stay has ended, his assistant David Wright has been handed temporary charge for the club’s League One swansong.

Wright started the season managing Maldon and Tiptree against Phoenix Sports in Ryman League.

Now he is preparing to take charge of the U’s penultimate game of the season at promotion-chasing Barnsley on Saturday.

To lose a manager with Keen’s coaching calibre after just four months is a real blow.

He was unable to save Colchester from relegation but nevertheless made a good impression, in the time he was at the club.

That makes his decision to leave all the more baffling.

While the reasons for Keen’s departure are still unclear, speculation is rife about why he made his exit.

In the immediate aftermath of Colchester’s defeat against Burton last Saturday, he talked about the club having a bright future and gave no hint of any potential resignation.

But his comments at his pre-match press call at Florence Park last Thursday lunchtime were particularly revealing.

“It’s been a tough day today,” he said. “A couple of things happened in training and around the training ground.

“It’s been a little bit of a tester of my managerial skills.”

Keen’s surprise decision to leave key players Alex Gilbey, George Moncur and Elliot Lee on the bench for the Burton game was equally intriguing, albeit it with the U’s relegated all bar the shouting.

Perhaps there are outside factors that have influenced Keen’s resignation?

There have been rumours linking Steve Clarke with the Celtic managerial job, which becomes vacant at the end of the season.

Having worked closely with Clarke at the likes of Liverpool, West Brom and Reading in the past, would it be any real surprise now if Keen joined his former colleague in the Celtic Park hot seat, should he be appointed?

Whatever the reason for his exit, it is a real shame for Keen and Colchester United that his short but eventful reign has ended so abruptly.