Must happen/Can't happen against Rams

SANTA CLARA, Calif. -- Here is a look at what the San Francisco 49ers must do and can't do Sunday at home against the St. Louis Rams:

Must happen: The positive strides the offense made in Washington on Monday night must continue. 49ers quarterback Colin Kaepernick completed six passes of 15 yards or longer. The 49ers have to stay aggressive offensively because that's when good things happen. That has to remain the mindset.

Can’t happen: Tavon Austin can’t take over. The 49ers did a masterful job against the dynamic rookie in Week 4 in a 35-11 win at St. Louis. But Austin has been hot lately and is a big reason why the Rams have become an explosive offense. Austin is dangerous in offense and in the return game. The 49ers must key on him and keep him from striking quickly and changing the complexion of the game.