According to Sam Caplan  via the print edition of the wrestling observer this fight could take place this fall.

After turning down a potential proposed light heavyweight bout vs. Brandon Vera at UFC Fight Night 14 on July 19, attention has turned to Wanderlei Silva’s next fight, which could take place in the fall.

According to the June 23 print edition of the Wrestling Observer, Silva’s likely next opponent is undefeated light heavyweight prospect Thiago Silva. The bout could take place in October despite the fact that Wanderlei Silva has reportedly asked not to be scheduled to fight again until December.

The Observer indicated that Wanderlei Silva was given a choice of facing either Thiago Silva or Lyoto Machida. A specific reason for while Thiago Silva is considered the more likely option than Machida was not given, although Dave Meltzer indicated that the UFC is having trouble finding willing opponents for Machida.

I personally would rather see Thiago Silva or Wandy vs. Lyoto Machida.  Simply, because I'm not quite sure that Thiago is THAT good just yet.  If he were to lose...no problem being that would be the first loss of his career and he can always be built back up.  Plus, I think Wandy's style could present Machida with problems he hasn't faced quite yet.   However, as stacked as the LHW division is in the UFC one really can't complain about any of these matchups.  My only question is...why would Wandy want to wait until December to fight..when his last fight lasted 36 seconds and took place in May?