Per TMZ Sports, Abel Sanchez called Alvarez an insult to boxing for failing a drug test earlier this year.
Canelo was suspended for six months by the Nevada State Athletic Commission for failing two drug tests.
He blamed the failure on contaminated meat in a statement released by Golden Boy Promotions, via ESPN.com's Dan Rafael:
"As part of the voluntary testing program that Canelo Alvarez insisted on ahead of his May 5 fight, one of his results came back positive for trace levels of clenbuterol, consistent with meat contamination that has impacted dozens of athletes in Mexico over the last years.
Upon receiving this information, Golden Boy immediately notified the Nevada State Athletic Commission and Gennady Golovkin's promoter, Tom Loeffler."