Alexander Gustafsson and Thiago Silva are both on the precipice of championship contention. Yet, each will enter the Octagon this weekend with very different levels of momentum.Silva has only fought twice in the last 27 months. A back injury and then a failed drug test following an impressive performance against Brandon Vera leaves Silva in light heavyweight limbo. His contender status could very easily disappear if he loses on Saturday night in the UFC on FUEL TV main event in Stockholm, Sweden…