No. You technically don't have to cook the rice before you add it to your soup. Some may say the rice will absorb a lot of the fluids in the soup, which is expected, but that's ok. The soup should have enough liquid to accommodate this when it does happen. Save time and don't cook the rice before you add it to your soup. If you do prefer to add cooked rice to the soup, do so when the soup is almost done and ready to serve. This will prevent the rice from getting too mushy.