Chambers has been training with his new team-mates
Castleford Tigers coach Terry Matterson says that sprinter Dwain Chambers will have to wait for "two to three weeks" for a possible debut for the reserves.
The 30-year-old is in his second week of a month's trial with the Super League club and hopes to earn a contract for the rest of the season.
"The St Helens game is the one that we're targeting in the next two to three weeks," said Matterson.
"He's doing a fair bit of work but Saturday is just a bit too short."
Matterson feels that Chambers - who made a second return to athletics earlier this year - still has more work to do before he can make his highly anticipated appearance.
"He's just continuing training - we'll continue to monitor him," he said.
"It may be just a bit too early for him at the moment.
"We'll make that decision later in the week."
Castleford are still to reschedule their game against St Helens reserves after it fell victim to the weather last Sunday.
Chambers completed a two-year drugs ban from athletics in 2005.
He won a silver medal in the 60m at last month's World Indoor Championships, but is banned from running in this year's Olympics because of a British Olympic Association by-law.