The 49ers have not indicated which quarterback they will start on Sunday.
While head coach Mike Singletary said in a press conference that he was unsure of who he was going with, you can be sure that this is completely untrue.
The 49ers have a long week to prepare for the Rams, as they played a Thursday game. This means that the coaching staff has had since Friday to prepare. The tape has been evaluated, and the 49ers probably knew sometime on Saturday who they were going with.
They will likely try to keep the starter a secret as long as possible. Singletary has accused the 49er organization of having a "rat" within. The 49ers have done a phenomenal job of keeping the starter under wraps.
So how do they benefit from the secrecy?
The Rams don't know who to prepare for. Troy Smith and Alex Smith are completely different quarterbacks. While both quarterbacks excel at throwing on the run, Alex Smith has a much better feel for the playbook and the offense in general, and Troy Smith does a better job at taking shots downfield and stretching the field.
The Rams may think they know who the 49ers may start, but it is all guesswork. Troy Smith won in spectacular fashion when he faced the Rams. Alex Smith was just blown out in a must win game against San Diego. This may lead the Rams to believe they should expect Troy Smith to start, but was one botched game last week enough to make Alex Smith see the bench?
If the 49ers can keep their starting quarterback under wraps for even one more day, the Rams will have to replicate the play of both quarterbacks in practice. Half the reps on defense game-planning against the will-be starter will in theory decrease their effectiveness against whoever gets the nod on Sunday.
This game has playoff implications for both teams. The Rams cannot game-plan with any conviction until they know exactly who is starting. This may seem like a small advantage for the 49ers, given that both quarterbacks are expected to struggle regardless of who gets the nod, but with jobs and the playoffs on the line, the 49ers need every advantage they can get.
I expect the 49ers will go with Alex Smith, simply because he gives offensive coordinator Mike Johnson more to work with. Troy Smith has experience against the Rams, but teams have put a stop to his accolades since they figured out he cannot succeed in any capacity as a pocket passer.
It is all speculation for everyone—including the Rams—which is exactly what the 49ers are trying to achieve with this facade of uncertainty they have created.