Aston Villa's chief executive Richard FitzGerald has quit - just over a year after joining the club, it was announced yesterday.

Mystery surrounded the resignation last night and Mr FitzGerald is not believed to have another job lined up, sparking speculation of a fall-out with Villa's billionaire boss Randy Lerner.

His departure comes little over a month after the appointment of former Wembley chief executive Michael Cunnah as the club's new chief operating officer.

The news, announced just before the close of the January transfer window, caught fans by surprise following the club's recent transformation under its new management team.

The last 18 months has seen attendances at Villa Park go up and sales of replica shirts at an all-time high in the wake of a more vigorous promotion of the Villa brand.

A short statement from the boardroom said: "Aston Villa Football Club today announces the resignation of chief executive Richard FitzGerald. The club has made significant progress off the field in the last 13 months and would like to thank Richard for his contribution during that period.

"The club wishes him every success in the future."

Mr FitzGerald was unavailable for comment last night.

According to Neil Heitzman, of the Aston Villa Supporters Trust, Mr Lerner may have decided it was time for a new man to take the club to the next level.

"The club is looking for someone to push it further forward. If Richard hasn't achieved that, it is right and proper that the club should bring someone else in.

"Aston Villa has made massive steps forward in the last 18 months in terms of its brand.

"But the club has to look ahead. We have a great manager and a really forward-looking board.

"It is difficult to gauge what is going on inside the club. My only assumption is it wants to take that step forward and maybe Richard understands if they want to make it a global brand they are looking for someone who can achieve that."

An accountant by training, Mr FitzGerald began his career with Deloitte Haskins & Sells in 1983. After qualifying as a chartered accountant, he moved to IMG, the leading sports marketing and media company in 1988.

He spent the next 18 years working for the company where he developed a specialist interest in the media and internet field, skills that made him attractive to Villa.

Mr FitzGerald's recruitment as CEO came months after Mr Lerner's £62.6 million take over the club in August 2006.

It followed the dawning of a new era, with Martin O'Neill replacing David O'Leary as manager, a move that won approval among fans.

Mr FitzGerald also gained plaudits for promoting a more open approach at the club and making sure fans had greater involvement.

In an interview with The Birmingham Post a year ago, he stressed he saw his role as developing the commercial and marketing side of the club.

He claimed the one thing Villa had lacked in recent years was a clear brand and made it a priority to focus on developing one, including the introduction of a new badge.

"We need to start by promoting the club in the West Midlands," he said.

"We are very aware that the local 5.3 million population is a vast potential supporter base and we will focus the core of our commercial ambitions here.

"Although the global growth of our fan base is presently not the club's most urgent priorities, it is nevertheless of strategic importance in the long term. "

Villa fans last night reacted to the news by posting comments on club-related chat rooms and blogs.

One simply said: "Who will take care of our marketing now?"

Another said: "Personally, I don't like this news and think that Mr FitzGerald was making strides in the right direction."

Others speculated that the club no longer had need for him since Mr Cunnah's arrival.