Mike Johnson revealed in the latest PWInsider Elite Audio that WWE had plans to turn John Cena heel back in 2012.
The plan was serious enough that Cena had new ring gear made, new outfits, and even a new entrance to go along with the heel turn. Ultimately WWE dropped the plan completely due to merchandising concerns.
“I don’t know who he was going to feud with. I don’t know if creative was ever “locked in”, but I do know that Cena had come up with a new ring entrance. He came up with new outfits he was going to wear. Things like that. It was probably around 2011 or 2012. So it was about four or five years ago from now. So yeah, it was right around the time he had the K-Mart kids campaign. So, if you google that and find out when that campaign was, it was pretty much around that time.”
Here is audio from back in 2015 of John Cena appearing on Chris Jericho’s podcast in which he discussed the planned heel turn: