Question: What rival league did the Spokane Shock join?
Sentence: On September 1, 2015, the Spokane Shock officially left the AFL and joined the IFL under the new name Spokane Empire, becoming the fifth active AFL/af2 franchise to leave for the IFL since bankruptcy (Iowa Barnstormers, Tri-Cities Fever, Green Bay Blizzard and Arkansas Twisters—now the Texas Revolution—left previously).
Answer in sentence: yes