The latest trend seems to be that if you compete in the Olympia, you then take a longer off-season and use it to improve for the next year. The result of this strategy is that several top competitors from the 2012 Mr Olympia are opting out of the 2013 Arnold Classic.
In my opinion, Wolf had the 2012 Arnold Classic in the bag. He had been preparing for that contest since November 2011. From then, Wolf had to maintain a relatively lean physique and not go into a deep off-season mode in order to come in sharp for the 2012 Mr Olympia. Failing to accomplish this, he went on to compete overseas, finally coming in a little sharper and winning the 2012 Prague Pro, thus stopping Shawn Rhoden's unprecedented winning streak.
With all that said and done, Wolf had been essentially dieting for a year. The need to take a break, get a good off-season and come in strong for the 2013 Mr Olympia is now his priority.
The official 2013 Arnold Classic list still is not out; however, we do know of a few that have already thrown their hat into the ring: Dexter Jackson, Ben Pakulski, Fouad Abiad, and Lionel Beyeke.
The only thing we know for certain is that there will be a new Arnold Classic Champion in March 2013. (Unless Dexter takes it - he's won the Arnold in 2005, 2006 and 2008.)