The first WWE programming on Fox is scheduled to air on Friday, September 27 at 8pm ET.
The one-hour "SmackDown's Greatest Hits" special is scheduled to air at 8pm ET that Friday night, on the main Fox channel, according to PWInsider.
The September 27 special is designed to be a preview for WWE coming to Fox. We noted earlier this summer that a preview special was being planned as a way to show non-WWE fans what to expect, as a way to introduce them to Superstars and the brand in general.
As noted, SmackDown will premiere on Fox Friday nights beginning with the October 4 episode. The show will then air live each Friday night from 8-10pm ET. The October 4 premiere will air live from the Staples Center in Los Angeles, and will be the SmackDown 20th Anniversary special.
The final SmackDown USA Network episode is scheduled to air on Tuesday, September 24 in the regular time slot, which means there will be more than 7 days in between regular blue brand episodes. This September 27 special will make it so that there will be at least some SmackDown content on TV before the October 4 premiere.