Ford's involvement (or non-involvement) has been the subject of much speculation since the project was revealed back in August 2011. Andrew Kosove, of production company Alcon Entertainment, was initially quoted as saying there was practically no chance of Ford showing up ("I think it is quite unlikely").
A few months later, however, a mischievous Scott suggested that, while Deckard isn't intended as the central character of the film, "It would be amusing to have him it somewhere". A few months later, Scott was musing about how Deckard having aged might be explained away in the film. "He was a Nexus 6, so we don't know how long he can live," he chuckled. Since Ford was never an adherent of the 'Deckard's a replicant' school of thought, you might think that would be a sticking point.
The assumption about Ford's reluctance to attend, however, has always been based on his much publicised ambivalence towards the original, and his fractious on-set relationship with Scott. His appearance on the lengthy Final Cut DVD documentary suggested that those wounds have healed though, and he now tells IGN: "I remember it with complication, but I'm not there to generate nostalgic moments, I'm there to do a job of work. I quite understand that everybody has an ambition when they come and do a film, and everyone's ambition may not be focused on the same thing. I truly admire Ridley as a man and as a director, and I would be very happy to engage with him again in the further telling of this story."
As for the infamous voice over, excised from all versions subsequent to the Theatrical Cut, Ford, of course, says, "That was a big part of the issue. I don't think it was necessary... and Ridley didn't think it was necessary. That was something that came up from the studio." So if the new film required narration? "I'm now capable of losing my voice: cutting out my tonsils and my vocal chords!"
Either way, the Blade Runner sequel is a long way off yet. Last we heard, Michael Green (Green Lantern) was at work on the screenplay, following an initial draft by original Blade Runner scribe Hampton Fancher. As always, watch this space for developments.