This could be one of the most unnecessary event preview stories in recent history. Or, if you’re not a fan of them in the first place, another piece for the scrap heap. Wherever you stand, it’s hard to argue that UFC 168, which takes place Saturday at Las Vegas’ MGM Grand Garden Arena, pretty much sells itself. And that’s even in this year’s crowded field of competition. The UFC has had a tremendous run of luck in 2013 as far as injuries go, but it’s also had that in terms of quality fights. Sure, there have been usual spates of stinkers.