YORK City Knights will be without in-form full-back Richard Wilkinson for at least a month and maybe as long as six weeks - a major blow ahead of Sunday's iPro Sport Cup semi-final.

Hard-running second-row Josh Tonks, one of the few players to impress in last weekend's below-par win over League One whipping boys South Wales Scorpions, is also a doubt for the Bootham Crescent clash against Gloucestershire All Golds - when York will be aiming to reach their first knockout final since 1978.

Wilkinson - the off-season recruit from Doncaster whom head coach James Ford has so far successfully changed from a half-back to a full-back - departed the Scorpions match in the first half having initially tried to play on with what appeared to be an upper arm injury. It is thought he has torn a tricep muscle.

Tonks came off late on with a hamstring injury.

"Richard has been excellent for us so, yes, it's a big blow," said head coach Ford.

"He's a competitor, he's got a lot of energy and he gives us a running threat, something that's really important to a team.

"I'm disappointed as he was doing a good job at learning the full-back role.

"What it will do, though, is give an opportunity for Brett Turner to have another crack at full-back."

Turner has not played since scoring a superb double, including a mesmeric long-range solo try, in the win over Rochdale in the iPro Cup quarter-final on April 3.

That made it five tries in five appearances since returning to the club, though all five have come on the wing.

Said Ford: "I fancy Brett as a winger but I'm not averse to working with him as a full-back. He's a dangerous runner and is solid defensively."

Tonks joined fellow back-rower Ryan Mallinder on the treatment table last Sunday, although Ed Smith was rested that day and is free to return this weekend.

"We're optimistic Josh will be available," said Ford, albeit cautiously, having been plagued himself by hamstring trouble in the latter days of his playing career.

"Josh was one of a couple of players who furthered their reputations last Sunday - he carried the ball well and contributed positively.

"But he tweaked a hamstring and whether he players obviously depends on the severity of the injury. I know first hand these things can be quite tricky to get right."

Meanwhile, Ford is confident the drab second-half show against South Wales - the Knights won the game 40-6 but drew the second stanza 6-6 against a side with only four wins in the last 34 months - was a one-off.

"As a group we know that was not good enough," he said. "It wasn't us in terms of the standards we've got.

"But for those players who play this weekend it's an opportunity to right those wrongs.

"We weren't miles away from where we needed to be but we didn't execute our kicking plan as well as we could have and we lacked ferocity in our contacts.

"We've been really nasty in how we've defended over the season but on Sunday, apart from maybe the likes of Harry Carter and Jordan Crowther, that was missing.

"We seemed to lack a bit of organisation - we sat back organising the next play rather than pushing on and organising on the run, which is something Jonny Presley (who was rested) brings in abundance.

"The players who came in will be better for the run, though, which will be important."

Asked if he was at all worried the team have fallen into a malaise which may continue, Ford said: "When we don't quite hit our standards, we as a coaching team spend a lot of time thinking about it.

"On this occasion I'm confident the players I've got are good players who, for a huge part of the season so far, have served up really good stuff. They had an off day collectively and we're all involved in that process.

"We all know we need to be better this week.

"We're not going to brush it under the carpet - players are held accountable for what they serve up. But I believe in this group and 40, 50 or 60 minutes of below-par stuff against South Wales does not change that.

"I'm sure come Sunday we'll again be doing all the things consistently well that had got us into such a promising position so far this season."