Stepping in for Danzig at lightweight will be BJJ black belt and Pan Am gold medalist, Vagner Rocha (6-1).
The replacement was confirmed by the UFC late Tuesday evening.
Rocha is part of Team Pablo Popovitch and is the head instructor at the BJJ Center of Pembroke Pines in Florida.
Rocha has fought on both, Strikeforce and Bellator cards. Four of his wins have come via submission, including his most recent bout, which took place against Jacob Clark (7-3) at MFA: New Generation 5 earlier this month.
For a complete line-up of the fights scheduled for UFC 131: Dos Santos vs. Carwin refer to our Upcoming Events page.