On this past Friday Night SmackDown, Paul Heyman announced WWE Champion Brock Lesnar was quitting SmackDown after Lesnar went to Vince McMahon and asked for a match against Rey Mysterio. Lesnar retained the title at Crown Jewel against Cain Velasquez and was then attacked with steel chair by Rey Mysterio.
Lesnar wanted some retribution, but the storyline is that RAW and SmackDown stars must stay on their on their brand and Vince turned down his request, so Lesnar quit SmackDown to go after Mysterio.
Lesnar is scheduled for this Monday's RAW, the WWE and Universal Titles are expected to switch brands, as well.
According to the latest Wrestling Observer Radio, this Lesnar story was scheduled to play out, but it was going to kickoff on Tuesday's premiere of WWE Backstage on FS1 at 11 pm ET. Last Wednesday, "huge news" was teased about the show's first guest, which may have been what WWE originally planned with Lesnar.
The change happened after WWE talent and crew were delayed in Saudi Arabia, causing multiple audibles to be called for Friday's show. Lesnar and Heyman weren't originally scheduled for SmackDown, but were contacted since so few got out of the country on time.