Castleford will be without Australian scrum-half Brent Sherwin for their Carnegie Challenge Cup quarter-final at Huddersfield on Sunday but are confident his ankle injury is not season-ending.

The former Canterbury Bulldogs playmaker missed the end of last season and the start of this campaign with ankle trouble and is still waiting to discover the extent of his latest injury, sustained in Friday's 16-6 engage Super League defeat at Hull KR.

"We're still waiting for the results of the scans," said Tigers coach Terry Matterson. "He had an operation in the close season and we're hoping the pin is still in place.

"The worst-case scenario is that he'll be out for the season but we're hoping it will be just a month.

"It's a blow because he's been very good for us this year. But we learned to play without him last year, especially at the back end."

Stand-off Rangi Chase, who has filled in at hooker for the last two matches, deputised at scrum-half when Sherwin missed the opening game of the season and is one of the options open to Matterson.

"We have a few options," he said. "Ryan McGoldrick, Richard Owen, Kirk Netherton and Dean Widders could all be back this week. There's going to be a couple of late calls."

Castleford will be without captain Ryan Hudson, the former Huddersfield hooker, who is still recovering from a broken arm.