Colchester United assistant manager David Wright says he had no idea that Kevin Keen would leave the club.
Keen parted company with the U's on Tuesday after four months in charge, leaving Wright, who was appointed by the former Liverpool and West Ham coach, in caretaker charge.
Colchester were relegated from League One at the weekend after a 3-0 defeat at home by Burton Albion.
"I've been really surprised, I didn't see it coming," Wright told BBC Essex.
"We came in on Monday and Kevin went across to watch the under-21s at QPR so it was generally a normal week, and then on Tuesday the news broke."
Wright, who finished his playing career at Colchester in 2014, is in his first coaching job at a Football league club, having worked in non-league and with Ipswich's academy.
"Kevin's been at some big clubs and worked at one of the biggest clubs in Liverpool, so to tap into all his experiences and his knowledge of how to do things has been invaluable for me," the 35-year-old added.
"Early on we were really unlucky in not getting the results, and I think if we did get the results back then we would have had a real positive end to the season.
"We tried to put our finger on it but we couldn't quite nail it down.
"We had the four-game spell of three wins and a draw and we really thought 'we've cracked it', but then unfortunately we had a couple of defeats after that."