Birmingham boss Steve Bruce admits he considered resigning over Matthew Upson's departure.
The centre-back secured a move to West Ham on deadline day despite Bruce's opposition to the transfer.
Bruce felt the Birmingham board should not have allowed Upson to leave, and concedes that the entire affair drove him to the verge of quitting.
Asked whether he had thought about handing in his resignation, Bruce told the Birmingham Mail: "For a moment."
Birmingham chairman David Gold has since explained that the reason for Upson's sale was the fear that he would stop giving his all for the club, but Bruce remains stunned by his board's sudden change of heart.
Bruce is especially peeved that other Championship clubs managed to keep hold of their most prized resources.
"I can only apologise if I led people to believe he was staying, because that's what I thought too," he explained.
"I felt there was no way we were selling him. I had put my point to the board a couple of weeks back and we were all in agreement.
"Something then changed. Whatever the reasons were, you'd better ask the people who employ me.
"I didn't think it was the right move and if you look at all our competitors, none of them cashed in, which I can understand.
"What's frustrating is that Gareth Bale didn't go, Giles Barnes didn't go, Curtis Davies didn't go, David Nugent didn't go.
"Offers came in for those players. A lot of clubs in this division kept hold of their star assets and that's what I wanted to do."