After making their way through the first five games relatively pain free, the 49ers suffered their first "significant" injury as left tackle Joe Staley suffered a concussion. Staley had to leave the game after the head injury and it was subsequently reported as a concussion. He suffered a concussion last year against the Arizona Cardinals.
The 49ers moved Alex Boone from right guard to left tackle, and moved Leonard Davis in to the right guard spot. Daniel Kilgore is also an option at right guard depending on how Davis performs.
Moving forward, Staley will need to pass at least two concussion tests. The NFL concussion procedure requires a concussed player be reviewed by an independent medical expert, and then subsequently by a team or league expert (not sure if it's one or both). It will take a couple days at least before we know Staley's status moving forward. Given the short week before Thursday Night Football, it would not be surprising if Staley sat. We'll see how quickly he is cleared.