Peterborough chairman Barry Fry has blamed James McClean's agent after his move from Derry collapsed.
The two clubs had agreed a fee of £275,000 for the winger but it appears the deal has now broken down.
"The agent was more interested in securing his own 10 per cent than he was in looking after his client, even though Fifa rules say he's only entitled to five per cent of any deal anyway," Fry told the Peterborough Evening News.
"We were offering a young player the chance to play Championship football and yet his agent seemed to think he was dealing with Manchester United not Peterborough United."
Peterborough, meanwhile, hope to finalise a deal to bring Wolves midfielder Nathaniel Mendez-Laing back to the club on-loan for the forthcoming season.
"But as one door closes another one opens," added Fry.
"I expect us to have Mendez-Laing back at the club by the end of the week."