Birmingham City manager Steve Bruce desperately wanted to retain Matthew Upson's services.
Blues lost their star defender on transfer deadline day following his switch to West Ham for an initial Â£6million.
Bruce had been hoping to retain Upson's services in order to boost the club's promotion hopes and has hit out at the Blues board - even though it is against his better judgement.
"The one thing I'm never going to do is getting into a slagging match with the board, especially on television," Bruce told Sky Sports News.
"I'm disappointed. I'm disappointed with what's happened. I think we've made the wrong decision. But, that's my opinion. They're going to see things differently.
"I'm paid to get on with my job and I will do, as best I possibly can.
"He's (Upson) been unhappy for weeks. Or he expressed his opinion that he wanted to go and speak to them.
"Once it gets to that stage you know. It's football. There are a lot of clubs in our division that have kept hold of their star assets.
"I wanted to do that too. I wanted to say to him 'Look Matt, listen I understand what you want to do, but in my opinion it wasn't quite right.'"