Here's a photo of the bearing shield:

shield.jpg

I have no idea if SRAM sells replacements for these or if you have to buy a complete GXP BB. Also note that some Oval cranksets come with BBs made by Praxis. They're GXP compatible, but I don't know how closely their design matches SRAM's (in other words, a SRAM bearing shield may or may not fit a Praxis GXP BB).