For his part, Garlick said: ''It's an opportunity that is impossible to turn down and one I am very excited to be taking. But of course, I am very conscious that I will be leaving Albion at the lowest point we have experienced in my eight years here.''
Garlick is likely to remain at the club over the summer to assist with preparations for the significant overhaul that the club will make should they get relegated.
He added: ''Albion has become my second home and come to mean everything to me and my family. It's always been a challenge but it is one I have relished every day and to be leaving it at this moment is not easy.''
"All I can say is that we are all keenly aware there is a major 'rebirth' to be planned this summer and I will do everything I can to help that process before I move on."
Chief executive at the club, Mark Jenkins, admitted that he had tried to convince Garlick to stay, but that the opportunity was too good to turn down.
He said: ''I have tried to persuade Richard to stay but the opportunity the Premier League have offered him is one anyone would find difficult to turn away.''
Jenkins added: ''He leave us with our very best wishes in his new post. We will be sorry to see him go as he has been an invaluable member of our senior team for a long time.''
As for West Brom's future, he said: ''I want to assure supporters that we remain determined to take an opportunity this summer to re-launch the club into a new and positive era.''