UFC officials announced the fight Tuesday. The promotion has yet to confirm a specific August date or venue for the event, though it's expected to take place in Philadelphia.
The two were originally scheduled to meet at UFC 118 last August in Boston, but Rivera was forced off the card due to injury. It was rescheduled for UFC 122 in November but fell through again when Sakara came down with flu-like symptoms.
Rivera (19-8) is coming off a second-round TKO loss to Michael Bisping at UFC 127 in February. The co-main event turned into a high-profile fight when the 39-year-old and his camp got under Bisping's skin by mocking him on Internet videos.
Sakara (15-8) will also look to rebound from a loss, as he dropped a unanimous decision to Chris Weidman at UFC on Versus 3 last month. The loss snapped a three-fight win streak for the veteran, his longest since joining the UFC in 2005.
Brett Okamoto covers mixed martial arts for ESPN.com.