Could be osteophytes ... could be cysts ... if the MRI comes back negative, it is likely that the talus is just sitting improperly between the calcaneus and the distal tib-fib joint. Most of these respond really well to joint mobilization (again in the absence of pathology).
Some PTs in San Francisco who might be able to help ...
Kimberley Parker
Elizabeth Pastore
Malini Thadani-Singh
Heather Davis
There's a whole list of California COMT's
here (who based upon the coursework they have taken and the certification they have passed I would say SHOULD be good).