UPDATED: PWInsider is also reporting the same story as the Wrestling Observer -- that the Rock is not at RAW tonight and WWE is trying to re-write major portions of the show.
They report that The Rock left for Los Angeles this morning, catching WWE completely off guard. There is major heat on him for leaving. This is not part of an angle, as Rock had been worked into WWE's future plans and was scheduled to be part of a major angle tonight to setup a program with Brock Lesnar or the Undertaker (more likely Lesnar) for WrestleMania 30. All those plans have now been thrown out.
ORIGINAL: According to wrestlingobserver.com, there is panic backstage at Raw right now. The show was scheduled to build to a segment where Brock Lesnar beat up Rock to set up next year's WrestleMania main event. The problem: Rock is not there and has reportedly gone home. Vince McMahon, the writers and producers are in the process of redoing the show, evidently believing the angle has been nixed. Nobody knows any details as to what happened past that. As of this time, the belief is that Rock is not appearing.
Also, there is a second major angle tonight to set up the main feud going forward and the Extreme Rules main event involving John Cena's next title defense. Word is that it is one of the things that has been planned for some time and was actually scheduled before Mania.