Dyer has been out of action since sustaining the problem just minutes into his debut on the opening day of the season against Bolton.
It was initally thought the damage would only sideline him until September, but the injury-plagued 32-year-old has now suffered a new problem.
He considered retirement when he was at West Ham, and many thought QPR were taking a massive risk when he signed in the summer.
Rangers boss Neil Warnock: "It's not looking good for Kieron, and it looks as if he will need a lengthy rehab.
"There seems to be new ligament problem at the front of his foot, and he has been in a lot of pain.
"I feel for the lad, especially after the training and effort he's made to get back.
"There has been talk we would maybe think of finding Kieron another club at Christmas, bearing in mind we have a number of new players.
"But I would like to keep him until the end of the season - he deserves that at least."