Easy question...... You start Rawls!
Here's why - Beast is not healthy. In the first 4 or 5 games of the season Beast looked slow, slow to the hole, and simply not himself. Then we see a Hammi injury, now an abdominal injury. That is not simple coincidence.
You don't see that with Rawls. Rawls is hitting the holes quick and with a purpose. You can say "well, that 200+ game was against a weak SF D. What about the 170 against Cincinnati? I believe Rawls has earned an opportunity for more carries regardless of what is going on with Lynch.
If this team manages to secure a wild card, It would be nice to see Beast healthier than he is now. Giving Rawls more carries now can only benefit Lynch in the near future this season, however long that is.
Next season is a whole new ball game. For now you play the players that give you the best chance to win. At the moment, that is Rawls!