DARYL Powell has confirmed George Williams is facing "a couple of weeks" on the sidelines.

The Warrington Wolves half-back and England captain missed his first game of the season when he was absent from the side that was beaten 23-14 by Castleford Tigers at the Mend-A-Hose Jungle on Friday evening.

Stefan Ratchford moved from centre to the halves alongside Peter Mata'utia to deputise, with Greg Minikin brought into the outside backs.

After the game, Powell confirmed Williams pulled out of the game during yesterday's captain's run with a hamstring complaint but is hopeful the talismanic playmaker will not miss too much action.

"He’s got a hamstring tweak," he said.

"We’re not 100 per cent certain on how long he’ll be out – we’re looking potentially at two or three weeks.

"George doesn’t get injured that much so I’m hoping it’s only a couple of weeks.

"We’ll get Drinky (Josh Drinkwater) back next week I think so we’ll have a couple more options there, and I thought Matt Dufty did well when he stepped up to 6.

"I’ll have to get my head around what that looks like."

Ratchford was forced from the field during the second half in West Yorkshire requiring a head injury assessment and did not return to the fray.

However, Powell confirmed the club captain had passed the concussion test, meaning he will be free to face Leeds Rhinos next week.