Which one did you install, the FXAA mod or the SMAA mod?
To UNINSTALL the SMAA version of the photomod, delete ONLY the following files from your MLB 2K12 directory:
To UNINSTALL the FXAA version of the photomod, delete ONLY the following files from your MLB2K12 directory:
Your game should work as normal when all of the files listed above (depending on which photomod you used) are deleted.