For quite some time, the Rock's presence at Extreme Rules had been up in the air, with many speculating that he would drop the title to John Cena at WrestleMania and promptly return to Hollywood thereafter. Last week, Nick Paglino of Wrestlezone.com reported that WWE and the arena hosting Extreme Rules had stopped advertising "The Great One" for May's pay-per-view event, leading to almost universal acceptance and a belief that John Cena would walk out of the MetLife Stadium with the WWE Championship.
This latest report, however, somewhat reignites the speculation as to the outcome of the match that is satirically being referred to as "Twice in a Lifetime". Outside of kayfabe, John Cena still has to be considered a heavy favorite for the bout, as his character fights for redemption, the WWE title and to go 1-1 with the "Brahma Bull", equaling their win and loss record and ensuring a likely third match in their rivalry.
However, now that the Rock has been scheduled for Extreme Rules, the possibility of him leaving WrestleMania 29 as champion remains. Although a slim chance, it is arguably more likely that Rocky will hold on to the title on April 7; as dropping the belt would mean him losing his rematch in May, and it is hard to fathom The Rock losing two pay-per-view main events in a row.
That being said, perhaps it would be best for Cena to win at 'Mania, and their rematch to occur the next month at Extreme Rules, that way there should not be a high chance of getting "Thrice in a Lifetime" at WrestleMania 30.
Now that the Rock is scheduled to appear post-WrestleMania, we have been given at least a shade of unpredictability in a WWE Championship scene that has been largely predictable since Hell In A Cell back in October.
If nothing more, this announcement has at least reduced Cena's chances of winning to 90%.