" Game manuals are protected by copyright, and normally cannot be legally distributed online. The exception to this rule are translations of foreign-language (specifically Japanese) manuals for import gamers, which are very useful to the import gamer and have met with no known objections from copyright holders so far." http://www.gamefaqs.com/features/help/entry.html?cat=27
Fast forward a year and a half and there is still no Michael Phelps game. And even if there was, it does not automatically mean he would be credited, he could just be licensed. Hes not credited in any games.