Per Kevin Acee and David Garrick of the San Diego Union Tribune, the San Diego Chargers are staying in San Diego this season but have reached an agreement with the Rams to share tenancy in Rams Owner Stan Kroenke's Inglewood stadium if the Chargers decide to head north to LA as early as 2017.
The agreement essentially pushes the city of San Diego to accelerate their effort to develop a stadium plan as legitimate as St. Louis. Ironically (and perhaps infuriatingly), the NFL has approved an additional $100m along with the $200m from the G4 loan program. St. Louis' stadium plan, which included $300 million, was derided by NFL Commissioner Roger Goodell for doing so. Goodell or any other league official has yet to clarify why St. Louis' proposal was "fundamentally inconsistent with the NFL's program of stadium financing" while San Diego was granted the additional $100m.
For now though, it means the Chargers will remain in San Diego for at least another season.