The above method will allow you to perform a factory restore to remove any signs of rooting with the use of Odin and your computer. All you need to do is perform the proper button dance to boot into Download mode on your phone which you don't need a screen/display to achieve. Once properly done, Odin will recognize the device showing your in fact in Download mode and can continue.
I have used this method myself and suggested it to others on the Captivate's sister phone the Samsung Epic 4g.
Why? If Sprint or Samsung decides to just replace the display when the boot the phone up they won't see any sign of you being rooted then to default you on the warranty.