In a length interview, Sum 41's Deryck Whibley spoke brielfy about the departure of his longterm bandmate, Steve "Stevo" Jocz. It doesn't shed too much light however:

I think we were all pretty tired and burnt out by the end of this tour. Or at least i know i was and still am. Touring can be tough after awhile. I respect him and his decision. He's the best drummer I've ever played with. But i was not that surprised. You would have to ask him [about the specifics]. I won't speak on anyone's behalf. All i can say is, in life nothing stays the same forever. Even if it's unfortunate. Things change people grow. Different responsibilities and goals become a factor in your decision making. At the end of the day you have to do what is best for you in your heart.

The band released Screaming Bloody Murder in 2011 and are planning a new release for 2013.