The England full-back is currently serving a 14-month ban for taking cocaine but last week Wigan Warriors confirmed they had signed him on a four-year deal ahead of his return in 2019.
Hardaker says he was sacked immediately by Castleford when his failed test came to light just two days before last season’s Super League Grand Final.
“I wasn’t surprised because I’d breached my contract, so it was fair enough,” said the player, who helped inspire the West Yorkshire club to their first-ever League Leaders’ Shield and Grand Final last term.
“But I tried to stay there and I said, ‘Look, can you keep me on, pay me minimum wage, can you keep me on..?’
“I expressed I wanted to stay. They did offer me a contract but it was a low one.
“My solicitors’ fees (to help reduce ban from two years) were through the roof and the contract didn’t match up to the fees, so I said, ‘Look, I can’t take that because my fees are nearly as much as my wage’.
“I think they understood. And then for four or five months, I heard nothing. I wanted to stay and repay them, but it wasn’t to be. I believe things happen for a reason and now I’m looking forward to this move to Wigan.”
Hardaker had initially joined Tigers on a season-long loan from Leeds Rhinos before the club paid a £150,000 fee to make the deal permanent last June.
Elsewhere, Huddersfield Giants captain Leroy Cudjoe is set to make his first appearance in nine months when they visit Salford Red Devils tomorrow.
The ex-England centre, 30, hasn’t featured since September as he recovers from surgery on a microfracture of his knee.
But he is in the 19-man squad as improving Huddersfield seek a fourth successive win to escape the bottom four.
Interim head coach Chris Thorman, expected to remain in charge with Australian Simon Woolford still not arrived in the UK, said: “We’re as excited as anyone with Leroy coming back.
“He could potentially start and has trained really well. He is super-critical of himself and he doesn’t want to be underdone but I keep telling him he’s ticked all the boxes in terms of the medical point of view, conditioning and S and C... you are available for selection from every department in the club...
“But Leroy being Leroy he is his own worst critic and he’s debating whether he’s ready or not. All being well he’ll feature and with the momentum we’ve got at the moment it’s another lift being able to talk about Leroy.
“Everyone sees not only his physical stature but what he’s done in the sport and for this club; we get a real leader of men back and leader in actions.”
Meanwhile, Giants prop Matty English, 20, has been rewarded for his excellent form with a new deal that sees him stay at the club until the end of 2022.
Wakefield Trinity make two changes for tomorrow night’s trip to Widnes Vikings with fit-again Chris Annakin and Max Jowitt returning and Liam Finn and Matty Ashurst dropping out of the 19-man squad.
Hull FC could give a debut to academy full-back/winger Jack Sanderson, 20, when they visit Warrington Wolves.
Kirk Yeaman, who came out of retirement at Magic Weekend, is not in the 19-man squad and England prop Scott Taylor has been ruled out but Brad Fash returns from a broken jaw.
Hull KR see winger Justin Carney back in contention for the visit of Wigan while centre Junior Vaivai’s knee injury is not as bad as first feared and he could feature also.