The two clubs had been in negotiations for around a fortnight over a fee for Duffy.
It is thought an agreement is particularly close but no formal bid has been entered by Rovers.
Talks of formal discussions between Rovers and Duffy are also said to be premature.
Reports on Monday suggested the 27-year-old had departed Scunthorpe’s training camp in Northumbria to talk with Rovers officials.
But Iron boss Brian Laws confirmed yesterday Duffy was still in training with the club.
The quick-off-the-mark comments from Scunthorpe are likely to have further annoyed Rovers officials.
Paul Dickov expressed his frustration that Laws had made public Rovers’ initial bid for Duffy.
And the timing of Swann’s announcement will only have exacerbated matters.
While negotiations with Scunthorpe continue, so do talks with potential signings and out of contract players.
Source: Donny Mad