I find it hilarious that he didn't want to come off a whiner because he's been whining in his promos for ages now.- Part of the reason why Brock Lesnar has returned and The Undertaker is working next week is because CM Punk won't be returning anytime soon and WWE needs star power on TV.
Before this past Monday, the plan was for CM Punk to come out on RAW and whine about losing at WrestleMania 29, then walk out of the company in the storylines. This was held off from the post-WrestleMania RAW because officials felt that Punk would get a big reaction from the post-WrestleMania RAW crowd. Another reason it was held off is because Punk wasn't happy with the verbiage they wanted him to use and didn't want to come off as a whiner.
A few weeks back, Punk had a big blow up with WWE creative and wanted to give his notice to quit the company. He went and worked it out with top WWE officials. At that time, it was decided that Punk wouldn't be working live events anymore, just TV and WrestleMania 29.
Between the backstage problems and severely tearing knee ligaments at WrestleMania, Punk was written off TV this past Monday at RAW. Punk will be fine once he rests up and lets his knees heal. Right now there is no set plan for Punk to return but word is that he won't be back until SummerSlam time.
The line about not being back till around SummerSlam stunned me at first with it being 4 months away, but a couple of months away to heal before returning to build up a presumable big matchup really doesn't seem too far fetched at all.