Liverpool have been advised against thrusting Virgil Van Dijk back into action too early as the Dutchman prepares for a lengthy and arduous period of rehabilitation once he has undergone anterior cruciate ligament surgery.

Van Dijk damaged ligaments in his right knee following Everton goalkeeper Jordan Pickford's rash challenge on Saturday – although it is understood Liverpool are reluctant to write off the defender's season just yet.

The Reds have been light on details and, given the serious nature of the injury, have not put a timescale on how long Van Dijk will be out for, but two knee specialists agree recoveries from ACL surgeries should not be rushed.

Shaun O'Brien, a fellow of the Royal College of Surgeons, told the PA news agency: "By far the hard bit is the rehabilitation.

"The average person is normally out for at least nine months before they get back to playing the sport that they want to do.

"Even the elite sportsmen might be starting to train or play some reserve games at the six or seven-month mark but it's nearly always a good year before they're back starting a game and being confident with their knee.

"It just takes a long time to settle down and build up their strength, control and coordination."

Van Dijk is one of the best defenders in the Premier League and his absences leaves a considerable hole in the Reds' backline as they look to defend their top-flight crown this season.

Andrew Goodall, a clinical manager and MSK physiotherapist at Pure Sports Medicine, told the PA news agency: "It's important to make sure you take the right amount of time for that individual to meet the criteria required.

"To achieve that in under six months is pretty unlikely, especially if you want to make sure they don't suffer a secondary injury which is always a potential risk if they're rushed back.

"It's going to be a lot of rehab. I expect that he'll do well but it will take time. The question is always 'will he get back to his pre-injury level'?"

Mr O'Brien believes the chances of a recurrence in the same knee are low but revealed the other leg is more susceptible following a recovery.

He said: "Contralateral injury is more likely to occur than you re-rupturing the same one. The re-rupture rates vary but it's probably in the region of a three to five per cent chance that it could re-rupture."

Mr Goodall thinks Van Dijk's position as a centre-back is a positive, adding: "He's not a winger, an attacking midfielder or forward where there's a lot of jinking and rapid change of direction.

"He's probably got a good chance of not having a secondary injury because of where he plays but this injury wasn't a change of direction or a non-contact injury. There's always risk as such."

Van Dijk released a statement on Sunday night vowing to "do everything I can to be back as quickly as possible".

Alan Shearer warned Van Dijk faces "a long, lonely and difficult road" in his recovery as the former England striker detailed his experience of his ACL injury while with Blackburn in the early 1990s.

"The good news is that Van Dijk will be back as good as ever, as quick and as sharp and proficient. An anterior cruciate ligament injury is no longer career-threatening as it was in the 1980s and before," he told the Athletic.

"I came back from mine and immediately had the best three goal-scoring seasons of my life.

"The less good news is that, for all of football's innovations in medical treatment, sports science and fitness, there is no shortcut and the timescale has not changed; you're still talking an absence of six months, minimum.

"The best pointer I can give to Van Dijk is to be conscious of that time, to accept it and be patient with himself. I'm sure he will.

"There's no getting away from it, he'll have a hard couple of months, but the light will reappear and he'll be back where he wants to be. I wish him luck."