Randy Orton has been away from WWE television since May with a back injury. His last match happened on the May 20 episode of Friday Night SmackDown when RK-Bro dropped the Raw Tag Team Titles to The Usos in a unification match. Post-match, Orton was laid out by The Bloodline to write him off television.
Orton was dealing with a serious back injury that WWE feared would cause him to undergo surgery and likely be out of action for the rest of the year. Dave Meltzer later reported that "there is a lot of concern regarding Orton's back injury and its severity."
When WWE originally wrote Orton off TV, the idea was that he would heal up on his own and come back later in the year. WWE knew what they wanted to do with him.
According to WrestleVotes via GiveMeSport, WWE’s plans back in May when he first left was for Orton to immediately turn on Riddle whenever he was back.
A lot of things have changed since then, with Vince McMahon resigning and Triple H now leading WWE creative.
Originally, WWE was going to have Orton and Riddle have a short tag team run with Orton turning on Riddle, but they got over so well with fans that they had a lengthy run as a duo.