UPDATEDx2: PWInsider reports that The Rock was actually scheduled to open RAW tonight with a promo about losing the WWE Title to John Cena, only to be attacked and taken out by Brock Lesnar and Paul Heyman. This would setup the WrestleMania 30 main event. With The Rock taking off without notice, WWE is trying to re-write the show. One person backstage described the scene as "chaos."
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.