According to reporter Ben Jacobs, Richard Hughes decided earlier this year to leave Liverpool and informed the club's owners that he wanted to move to Al Hilal for a new challenge after the summer transfer window closed.

Liverpool had known for some time that Hughes would leave in September this year, but all parties agreed to continue working together until the end of the summer transfer window. The club believes Hughes played an important role in helping new head coach Iraola settle into the team and in completing the signing of Bradley Barcola.
It is worth noting that while Hughes was still Liverpool's sporting director, he never applied to work for Al Hilal, and Liverpool never granted any relevant permission. Liverpool confirmed that they are certain Hughes did not undertake any work related to Al Hilal this summer.
Liverpool has now begun the search for a new sporting director, with the process being led by Fenway Sports Group president Mike Gordon.
After Hughes' departure, Liverpool's existing football management structure will not undergo any other changes. Fenway Sports Group technical director Julian Ward, football development director Pedro Marques, Liverpool assistant sporting director David Woodfine, chief scout Barry Hunter, and the senior management team at the AXA Training Centre will all continue their duties as normal and report to Mike Gordon.