Coates was tipped to have signed a two-year deal with the Storm following several reports from earlier this week, with Ponissi stating that while Melbourne remain in the race for the Origin gun, nothing has been finalised.
“No he hasn’t signed, I wish he had,” Ponissi said on SEN 1170.
“We’re certainly, like a few other clubs are in there, and we hope he does sign for us.
“But, he’s got a big decision to make, whether he leaves the Broncos, and if he does there’s probably two or three clubs that are very much interested in him.
“We hope that he gives us consideration.
“I wish it was true, and we’re hopeful.
“But, he’s got a big decision to make and we’re just hoping like the rest of the clubs to be honest.
“But, he hasn’t signed for us at the moment, no.”
The 20-year-old was understood to have turned down more lucrative offers from all three Queensland clubs in favour of a cheaper deal with the Storm.
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Coates has long been linked to a move down to Victoria after first meeting with Melbourne coach Craig Bellamy late last year.
The Maroons winger has played 23 games for the Broncos after making his debut in 2019, showing plenty of promise at Red Hill.
His potential departure would be another massive blow for Kevin Walters’ hopes of retaining a majority of his young stars.
The Broncos announced on Wednesday that gun centre Kotoni Staggs has inked a four-year extension with the club, with Coates likely the next name on their hitlist.
With Coates seen as the perfect successor to the departing Josh Addo-Carr at Melbourne, the acquisition would be a great coup for Bellamy, who has recently managed to take the careers of Brenko Lee and Reimis Smith to new heights under his tutelage.