Vieira’s management, Alchemist MMA, announced his new contract with the promotion on Thursday, while MMAJunkie.com reported Green’s signing.
Vieira (12-7-1) is a member of the famed Brazilian Top Team in Rio de Janeiro, and is credited with creating the Anaconda choke. The 32-year-old has been fighting in mixed martial arts competition for the past decade, primarily in Japan and Brazil.
The King of the Cage lightweight champion, Green (15-4) is a well-rounded fighter that has a penchant for finishing his opponents. He has been decisive in 13 of his 15 victories. Green is 4-1 in his last five fights leading up to the bout with Vieira.
Strikeforce Challengers 18 is headlined by a bout pitting Jorge Gurgel against Joe Duarte on Aug. 12 at the Pearl at the Palms in Las Vegas.