WWE reportedly had two scripts written for Sunday's Night Of Champions pay-per-view prior to today's news that Roman Reigns had to have emergency surgery on a incarcerated Hernia.

One of those scripts didn't feature Reigns wrestling and despite rumors of his injury being a "work", it is being reported as legitimate and is being taken very seriously by WWE. 

The WWE creative team are now working solidly to re-write three day's worth of television before Sunday afternoon. 

It's not confirmed  but there is speculation that WWE had a backup plan for Reigns replacement against Seth Rollins at Night Of Champions but that fell through and this is why the WWE Network update on Reigns was delayed by some 90 minutes.