My knee is not right - I'm really only playing at half pace Great Britain skipper Paul Sculthorpe

The results appear to show a repeat of the injury which kept the 28-year-old out of last year's Tri-Nations.

But Saints coach Daniel Anderson said Sculthorpe had several options open to him, including playing on for the rest of the domestic season.

He will be in the 20-man squad to face Leeds before a final decision is taken.

Sculthorpe is still at risk of missing the Tri-Nations series for the second year in a row as the club consult medical experts to decide on the best way forward.

"We're exploring any medical avenue we can to get some answers and then get some scenarios," said Anderson.

"We are trying to find a couple of big-wigs in the field of knees to get their opinions. I can't put a time on it but it may be later this week or early next week.

"One scenario is to just keep going as it is now. He goes from training session to training session and from game to game and we get him onto the field: that's what he's done for the last six months.

He would like to regain some facets of his game which he feels he hasn't been able to contribute this year St Helens coach Daniel Anderson

"He could play week-in, week-out but he's not comfortable about the strength component.

"Hopefully, we will get some medical advice which will give us some other scenarios that are better than that and we will make a decision from there."

Sculthorpe, who was withdrawn during the Saints' 34-12 win over Wakefield on Friday, succeeded Andy Farrell as Great Britain captain in May 2005 but missed that year's Tri-Nations after undergoing major surgery.

He has only led the Lions out once since taking the captaincy, and had to come off early in the 46-14 win over New Zealand in June with an injury to his left knee.

"My knee is not right," Sculthorpe, who captained the Super League leaders to victory in the Challenge Cup final in August, told the Daily Mail on Monday.

"I'm getting pain between the joints and I'm really only playing at half pace."

Anderson admitted the final decision would lie with Sculthorpe.

"Everything is driven by the player," said Anderson.

FIVE LIVE VIEW Sculthorpe's withdrawal should give Rob Purdham the GB spot he so thoroughly deserves NK Five Live: Have your say

"His comfort level and his welfare is the most important thing and also his capacity to be confident in his ability on the football field.

"Ultimately the decision will rest with Scully himself. He's buying into everything.

"He would like to regain some facets of his game which he feels he hasn't been able to contribute this year. I think you can see the frustration that he's probably feeling."

Sculthorpe, a two-time Man of Steel, only featured in 16 games last season because of persistent hamstring and back injuries and the operation on his knee problem.

The Tri-Nations tournament - which this year is being held in Australia and New Zealand - gets underway on 14 October, with Britain's first Test on 28 October against the Kiwis.