The hosts have named Asaeli Valu, Uve Helu, Amanaki Lelei Mafi, William Tupou, Ataata Moeakiola, Lemeki Romano and Nakajima Isileli.
Mafi received minor injuries in their warm up match against South Africa but was given the green light for the RWC.
The powerful No.8 and and flying wing Kenki Fukuoka were both forced from the field, leaving head coach Joseph with some headaches ahead of his side's Pool A opener against Russia in Tokyo on Sept. 20.