They are understood to have had numerous differences of opinion in recent months, with the manager unhappy about constant speculation linking his right-hand man with various clubs in Spain.

Ayestaran had been lined up for the role of director of football at Athletic Bilbao last year, but the job did not materialise - the presidential candidate who made the offer failed to win an election to gain power at the club. A return in a backroom capacity to Valencia, where he worked alongside Benitez as the club won two Spanish titles, has also been mooted.

A specialist in sports science and player fitness, Ayestaran is known to have grown unhappy with Benitez taking a greater role in the training regimen, but the split remains a surprise due to the long-standing partnership forged by the two men.

While Ayestaran has yet to formally leave Anfield, Benitez admits it is unlikely that he will be able to persuade him to stay. "He said that he would like to leave the club, so we are now analysing the situation," Benitez said. "It came as a surprise because we've worked together for 11 years."