One day after UFC 153's top two fights fell out, two more took their place.
The bout replaces the planned featherweight title bout between champion Jose Aldo Jr. and Frankie Edgar. Aldo had to pull out of the fight on Tuesday due to complications from injuries suffered in a recent motorcycle accident.
The new co-main event features a battle of Brazilian light heavyweights as Glover Teixeira (18-2) faces Fabio Maldonado (18-5). Maldonado replaces Quinton "Rampage" Jackson, who also had to pull out due to injury.
MMAFighting.com confirmed the bouts after an initial USA Today report.
Silva (32-4), who will celebrate his record sixth anniversary as middleweight champion the day after UFC 153, has twice stepped up and fought at 205 during his record streak of 15 consecutive UFC wins. Both were first-round knockouts, as he stopped James Irvin in July 2008, and took out former champ Forrest Griffin at UFC 101.
Silva previously stated he was done competing at light heavyweight, but the opportunity to save a show and fight in front of Brazilian fans was apparently too much to resist.
Bonnar (14-7), meanwhile, is most famous for his bout against Griffin in "The Ultimate Fighter 1" finale. Bonnar has won his past three fights.
Teixeira made an impressive company debut at UFC 146, when he stopped Kyle Kingsbury. While there were strong rumors on Wednesday that Thiago Silva would take Jackson's spot against Teixeira, the spot instead went to Maldonado, who was slated to meet Cyrille Diabate at UFC 154. Maldonado is 1-2 in UFC action, most recently coming out on the losing end of a controversial decision against Igor Pokrajac on May 15.