If true, this UMD-less Patapon sequel's invasion appears to be a test run, for not only for digital distribution, but for Dave Perry's anti-UMD PSP2. We've contacted Sony for comment and will update if we hear anything.
Update: Sony's senior director of corporate communications sent us the following statement: "We're considering a digital only format for the Patapon 2 release as a one time test case as we continue to explore consumer preferences for digital content. The downloadable game will be available on May 5th at both retail and via the PlayStation Store. We remain focused on providing superior games and entertainment experiences in both the UMD and digital formats and are working closely with our partners to deliver the best PSP line up in our history. "