Hardaker was placed on the transfer list, with a £350,000 price tag, at the start of June and joined Australian club Penrith Panthers on loan later the same month, with James Segeyaro moving to Leeds in exchange.
He is now back in England and Hetherington said there has been “a fair bit of interest” in him from Super League clubs.
“We are awaiting developments,” Hetherington confirmed.
“He is on the transfer list, he is available and we are open to offers.
“There has been some interest in the last week or so.”
Castleford Tigers are understood to be leading the chase for Hardaker, who was hailed as the top player in Super League last year.
The 25-year-old was born in Pontefract and played for Featherstone Lions before moving into the sem-professional ranks with Featherstone Rovers, who were then coached by current Tigers boss Daryl Powell.
Salford Red Devils and Huddersfield Giants have also been linked with Hardaker and Hetherington said a return to the NRL is not on the cards.
“His preference is to stay in Super League, rather than go back to the NRL,” Hetherington said.
“The experience [on loan at Penrith] has formalised his own view of what he wants to do.
“Six months ago he wanted to go to the NRL for 2017, but that has changed in his eyes.
“He remains on the transfer list and we are open to offers.
“We are committed to securing the best-possible arrangement for Leeds Rhinos.
“We are awaiting a firm proposal from the clubs who are interested, but there has been some progress in the last week or 10 days.”
Segeyaro, who signed a two-year contract after an initial loan spell, has effectively taken Hardaker’s place in Rhinos’ squad for next year and Hetherington played down the prospects of a signing being made if the full-back departs.
He said: “We started to make our plans irrespective of Zak’s situation.
“We have gone ahead with those in terms of retention of players and the only player to have left is Mitch Achurch. He left a void to fill and we have addressed that with the signing of Jack Ormondroyd [from Featherstone], and James Segeyaro.”
Asked if Rhinos could recruit before the start of next season, Hetherington said: “Our focus is very much on the squad we’ve got and the emergence of the young players in the squad, providing an opportunity for them.
“We have seen the emergence of Ash Handley, Jordan Lilley and Ashton Golding and possibly people like Cameron Smith, Mikolaj Oledzki, Jack Ormondroyd and Jordan Baldwinson. It is an interesting time for the young people who have already shown progress and ability. That’s the competition for the more experienced players.”