Dwain Chambers says he is "optimistic" he will be able to compete in the Olympics this summer.

Chambers has begun a one-month trial with engage Super League strugglers Castleford Tigers but admits a legal challenge to his Olympic ban for failing a drugs test is "likely".

The 29-year-old has served a two-year drugs ban but is banned from running in Beijing because of a British Olympic Association by-law.

Speaking about an appeal, Chambers said: "We remain optimistic, we can't afford negative thoughts.

"There will be a decision on that in the next couple of weeks if we want to go forward with a legal case."

Chambers' solicitor, Nick Collins, added: "It's always been a very realistic aim we will be going there (Beijing).

"There's been some very encouraging comments from people outside the BOA saying they have no problem with Dwain.

"We wouldn't take it (an appeal) on if we didn't think there would be a reasonable chance of success.

"It's likely."

Chambers insisted the Olympics remains his priority but felt he had to explore other options should his appeal fail.

"I would like to get to Beijing - I'm getting on and am 30 on Saturday and this may be my last chance,'' added the sprinter, who said he would be taking advice from rugby league legend Martin Offiah.

"But I am here to learn and see if I can grasp a different sport.

"I'm going to take it one day at a time and instead of running in a straight line I will be running left and right.

"I'm optimistic about what I can achieve. I'm competitive at heart and want to go out and do the best I can.''

Chambers has a "good chance" of making his debut against St Helens on Sunday, according to coach Terry Matterson

Chambers looked visibly shocked when told the news at a press conference, but the Tigers have the smallest squad in Super League and lost Mark Leafa and Kirk Dixon to injury in Sunday's 50-4 defeat at Bradford.

"He's probably 50-50 at the moment," said Matterson. "We're busted. We only had 17 players yesterday and lost two more to injury so you do the sums.

"I would say his chances of playing in the first grade are high. We have a gym session tomorrow and he can lead the way in that.

"Because of the situation we're in, we won't be doing much contact work this week."

Chambers admitted at the press conference that he knew little about rugby league and had to be prompted by his solicitor Nick Collins when asked how many players made up a team.

"It's a long shot but you never know," said Matterson.

"The club can't lose anything by this. If he does make it, it will bring people through the gates."

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