Board Thread:Questions and Answers/@comment-24213465-20131027181510/@comment-679780-20131031214709

Well the first time, Jason Griffiths to Ryan Drummond, was because Sega preferred the 4Kids actors over there own. This caused quite an uproar in the Sonic community.

However as now it's Roger Craig Smith. Could be Sega either renews it's voice actors of their contracts every five years or so.