PWInsider.com has confirmed with sources that the injury is to Elias' ankle and the decision was made today not to let him perform.

The original WWE announcement on the situation read:

Due to an injury, Elias will not compete in his scheduled King of the Ring semifinal match against Chad Gable. 

Stay with WWE Digital platforms and watch SmackDown LIVE tonight on USA Network at 8/7 c for further updates as the situation develops.