The engage Super League strugglers say they saw encouraging signs during the controversial athlete's month-long, unpaid trial, but they do not have time to spend grooming him for rugby league.

Chambers, 30, who experienced his first taste of rugby in a specially-arranged reserve grade game 10 days ago, must now hope that clubs outside Super League saw enough potential to make him an offer.

"I am in discussions with other clubs," said Chambers's agent Ron Hill, "but it's got to be right from day one. It was all a bit rushed last time. I have had one or two clubs coming to me, but it's got to be full-time.

"Dwain needs six months in the reserve grade and a full pre-season to learn about the game.

"We know he's mentally tough and he's got speed. He has come a long way in a short time and I think what we've seen in a month is enough to show there is potential."

Chambers, shunned by athletics since his return from a two-year drugs ban, spent 39 minutes on the field in four spells of last month's friendly match and clearly struggled to cope with the stamina needed to play the 13-man game before eventually retiring with a shoulder injury.

He insisted, however, that he enjoyed the experience and Castleford chief executive Richard Wright claimed the exercise was worthwhile.

Wright said: "During his trial period Dwain has been a joy to have around. His work ethic and professionalism have been exemplary."

He added: "However, our coaching team feels that he would need a significant amount of additional time to prove whether or not he would be capable of making the grade in Super League and time is something that we don't have.

"Furthermore we have an outstanding group of young players coming through whom we need to focus upon and give our attention."

Chambers's manager Nick Collins said: "While disappointed, Dwain is comfortable with and understands the decision. He leaves the club in a positive mood and with a smile on his face."

Chambers has not yet ruled out an attempt to over-turn the British Olympic Association ban on him competing in Beijing this year and also has hopes of running in the London Olympics in 2012.

Huddersfield centre Jamal Lolesi is facing a threat to his ever-present record after being charged by the Rugby Football League with verbally abusing match officials.

The former New Zealand international is alleged to have twice used foul and abusive language during the Giants' 36-34 defeat by Warrington in Cardiff. He will appear before the League's disciplinary panel in Leeds today on a grade C charge, which carries a suspension of up to four matches.

The League's match review panel decided not to cite Wigan scrum-half Thomas Leuluai for a trip during his side's 57-16 defeat by St Helens.

Hull centre Craig Hall has ended speculation over a switch to city rivals Hull KR by agreeing a new two-year contract at the KC Stadium.

The 20-year-old son of former Rovers player Dave Hall is now committed to the club until the end of the 2010 season.

St Helens have renamed Knowsley Road, one of only five grounds still in existence that staged fixtures in the inaugural season of the Northern Union in 1895. It will now be called The GPW Recruitment Stadium after Saints secured a sponsorship deal.