It appears WWE adding Dean Ambrose to the Payback main event with Randy Orton, Roman Reigns and WWE World Heavyweight Champion Seth Rollins was a late decision. Cable TV ads that aired after this week's RAW were still listing a Triple Threat main event without Ambrose.
It's interesting that WWE is putting all of the former Shield members in a main event already as that was first discussed as a potential WrestleMania 32 idea.
On a related note, Sunday's Fatal 4 Way match gives WWE the chance to turn Ambrose and Reigns on Orton. The company is lacking in credible heels but they do have new babyfaces that they could be pushing.