According to Weezer's website, Rivers suffered a punctured lung and injuries to his spleen but is on the mend. His assistant, Sarah Kim, was also injured but has since been released from the hospital.
The December shows for their Raditude tour have been cancelled, including DC101's Festivus tomorrow that I had planned to cover. I'm not sure if that particular show will be rescheduled or not, but I will post details if it is.
Many prayers going out to Rivers and Sarah!