That seems like an awfully difficult case for him to win. Even if a U.S. government official is involved in an investigation of a matter that is totally bogus, it's not necessarily the media's job to ascertain the legitimacy of the allegation. The investigation is a legitimate news story even if the underlying allegations against the target are false.
And if the Yahoo story is accurate when it claims Page didn't respond to requests for comments, then how can he possibly prevail in a lawsuit? They gave him every opportunity to deny the allegations that were the basis of the investigation, right?