YORK City Knights have suffered a huge blow a little over a fortnight before their big opening pre-season friendly after winger Ben Dent was told to stay away from rugby league for three months.

Dent was sent to hospital by the club's medical staff this week after suffering severe headaches during hill training.

Doctors have ruled out the worst-case scenario - bleeding on the brain - but are unsure what is causing the migraine-like symptoms so have told the 24-year-old to rest up as they try to figure it out.

Dent, the Knights' top try-scorer in 2014, will therefore not feature in any of the three planned pre-season friendlies, which start with the prestigious visit of Hull FC on Sunday, January 3, for the club's long-awaited first outing of their new tenure at Bootham Crescent.

He's unlikely to play in iPro Sport Cup or Challenge Cup ties in February and has only an outside chance of being ready for the start of the League One season on March 6.

Said head coach James Ford: "Ben has had tests and thankfully they've not found a bleed, but they are obviously worried and have advised him not to do any contact work for a number of months until they have got to the bottom of the issue.

"We're all worried for Ben. It's good in a way that is was not a bleed on the brain, which was the worst-case scenario. But he's off work and it's a period of bed rest for him now.

"He's a player we will miss, as a winger, a full-back and as an individual around the club.

"We won't rush him back. When he's ready to come back we will bring him back in slowly.

"He might be okay for the start of the league season but we'll have to get him up to speed and see what form the other boys are in."

Ford said the problem is almost certainly unrelated to anything that has occurred in training.

"That was a worry for me as Ben's coach and friend and it was one thing I was keen to find out," he said.

"It occurred when we were doing some hill work. It was getting worse so our medical staff told him to go to hospital.

"It transpires that the doctors don't think it's anything to do with what we've done in training.

"We're lucky the medical team were on the money to send Ben across and get him checked out and that nothing more serious has come of it."

Asked if Dent had taken a head knock in training, Ford said: "There was nothing we're aware of that could have triggered it.

"Training has been intense and vigorous but we're talking tough, athletic boys, and nothing that should contribute to something like this."

The Knights were already going to be without fellow winger Austin Buchanan for pre-season after his hernia operation, while number one James Haynes is on the long-term injury list after his knee reconstruction.

It leaves new boys Jordan Grayston and Brett Turner tussling for the full-back berth against Hull, while Adam Dent and utility back Tyler Craig are left vying for a wing spot, with Nev Morrison a likely starter on the other flank.

Said Ford: "It's a little bit of adversity for us to deal with, but we're used to adversity after last year and it makes us stronger.

"It does give an opportunity to Brett Turner and Jordan Grayston at full-back and Adam and Tyler on the wings certainly for the short to medium term.

"If they train and play well, they stay in the team, so it offers opportunities.

"The most important thing is we all support Ben through it. He's got the talent to come back in once we make sure he's okay to play."