The shuttle crew took a closer look at the gouge in the heat shield using among other things a laser to collect data that would allow a mockup to be made here on earth, and then run through the simulator to see if a repair needs to performed.
At this point NASA is feeling pretty confident that no repair will be needed as NASA has seen these types of gouges in the past. You would think that after all this time they would have figured out how to get past these incidents. BBC