Jim Harbaugh has announced that he will know which quarterback will start for the San Francisco 49ers by midweek.

Colin Kaepernick has started the last two games for the 49ers, after Alex Smith sustained a concussion against the St Louis Rams.

The 49ers coach told reporters: "Alex Smith is our starting quarterback. He has not done anything to lose that job. In fact, he's playing at a very high level.

"Also, Colin Kaepernick, you can't categorise him as a backup quarterback, because he's started games and played very well in those games.

"So in a unique situation, you have two quarterbacks that are playing at a very high level. One's your captain, your starting quarterback. The other has played great football the last three football games."

San Francisco face the Rams again this Sunday.