Question: What is the nickname of the boxer who was offered to fight against Sergio Martinez in Atlantic City 2011?
Sentence (from "Sergio Martínez vs. Darren Barker"): The fight took place in Boardwalk Hall, Atlantic City, New Jersey, United States on 1 October 2011 Barker, the European champion, was certainly not the first choice for Martinez, various other potential opponents turned down overtures for a bout against him.
Relevant evidence: Yes