Leeds United executive director Adam Pearson has left the club after just four months at Elland Road.
In an open letter on the Championship club's website, Pearson said he made the decision so he could focus on other personal and business interests.
"It is with a huge level of disappointment that I cannot continue to contribute," added the former Hull City and Derby County chairman.
Leeds owner Massimo Cellino said he was keeping the role open for Pearson.
"I hope to welcome him back at some point in the future," added Cellino.
Leeds manager Uwe Rosler said he was "devastated" to learn Pearson had left.
"Nobody saw it coming," said the former Brentford and Wigan Athletic boss.
"The only thing I can say is that the working relationship between Adam and myself and Adam and Mr Cellino had been very good.
"You can believe me by that. I hope to see him again some day."
Leeds are currently 14th in the league after suffering their first league defeat of the season on Tuesday against Ipswich.
Pearson left Sheffield Wednesday in May to assist Cellino in the running of the club.
He had previously worked as Leeds' commercial director before going on to purchase Hull City in 2001.
"It is with great disappointment that I have to confirm I'll be taking a break from Leeds United and football in general, in order to focus on other personal and business interests," he added.