Fozzy is scheduled to perform on September 16th, which is the night of the WWE Night of Champions PPV. At this time, it is considered highly unlikely that Jericho will work the pay-per-view.
The festival doesn’t have anything scheduled for Monday’s, likely for travel reasons, which means that Jericho could possible still work RAW before flying out for his next performance. Clearly, he’ll be a VERY busy man during this time.