UFC officials announced the change on Thursday. Bocek also confirmed his injury, which was sustained during training for the fight.
One of the top lightweight prospects in Canada, the trip to Toronto will be a short jaunt for London, Ontario’s Ronson. He has a 13-2 professional record and is currently riding an eight-fight winning streak.
His hit list includes a victory over Ryan Healy, the brother of UFC fighter Pat Healy, who is also fighting on the UFC 165 event.
Prazeres (16-1) is making the move down to lightweight for this fight after losing to Paulo Thiago in his Octagon debut at UFC on FX 8. The loss to Thiago was in a welterweight bout.
UFC light heavyweight champion Jon Jones will put his belt on the line for a record-setting sixth time when he faces Alexander Gustafsson in the UFC 165 main event on Sept. 21 at the Air Canada Centre in Toronto.