There's been a lot of speculation that WWE could be punishing John Cena for his refusal to compete at Crown Jewel, hence why he was pinned cleanly by Finn Balor on Monday's episode of RAW.
"Although the timing is suspicious, sources close to WWE stated there was no connection between Cena taking the loss and his recent decision to withdraw from the controversial “Crown Jewel” show in Saudi Arabia this past November," explains Justin Barrasso of SI.com. "In fact, I was told Cena offered to take the fall in an effort to make Balor an even bigger star."
Dave Meltzer, meanwhile, has said that Cena's purpose at this point is to help put over other talent and it's fair to say the leader of the Cenation has been doing a great job of that since he returned.