Following the announcement of Joe Riggs being out of UFC Fight Night 51 due to an accident at his home, Paulo Thiago will now meet Sean Spencer on the September 13th fight card in Brazil. 
UFC officials announced the new opponent for Thiago on late Tuesday afternoon.
UFC Fight Night 51 will come from the Nilson Nelson Gymnasium in Brasila, Brazil and will be headlined by a heavyweight bout as Andrei Arlovski meets Antonio Silva.
Spencer (11-3) has gone 2-2 since entering the UFC early last year and all three of his fights in the promotion have gone into the third round. After winning back to back fights against Yuri Villefort and Drew Dober, he was defeated at UFC 171 in March when he lost a split decision to Alex Garcia.
Thiago (15-7) has dropped back to back fights and six of his last eight. He is coming off a decision defeat at The Ultimate Fighter Brazil 3 Finale against Gasan Umalatov and his last win took place last year at UFC on FX 8 against Michel Prazeres. He was initially scheduled to meet Mike Rhodes on this fight card, but an injury pulled him out of the fight.
The current UFC Fight Night 51: Arlovski vs. Silva II is below.
Andrei Arlovski (22-10) vs. Antonio Silva (18-5)
Gleison Tibau (29-10) vs. Piotr Hallman (15-2)
Leonardo Santos (12-3-1) vs. Lukasz Sajewski (13-0)
Sergio Moraes (8-3) vs. Santiago Ponzinibbio (19-2)
Igor Araujo (25-6, 1NC) vs. George Sullivan (15-3, 1NC)
Paulo Thiago (15-7) vs. Sean Spencer (11-3)
Jessica Andrade (11-3) vs. Valerie Letourneau (6-3)
Rani Yahya (19-8, 1NC) vs. Johnny Bedford (19-11-1, 1NC)
Godofredo Pepey (10-3) vs. Dashon Johnson (9-1)
Francisco Trinaldo (14-4) vs. Efrain Escudero (22-8)