I think a lot of you are underestimating an NFL team way too much. This 49er game is no where near a guarantee.
Clutch, though I agree with you, that underestimating any team is a bad idea, what you need to understand, we now have three very important quality O-linemen that are shaky, put one in too early and that player may end up done for the rest of the season when we will really need them.
If you can get away with giving those guys a bit more recovery time, in the end, it will benefit the team more.
Ajayi has proven he does not need much room to succeed, run the ball, move around Tannehill a bit, and try to play a smart game at home while those guys heal for the away Ravens game.