CM Punk back in 2011 had his "Pipebomb" moment on WWE TV and behind the scenes where he was very unhappy with certain things within the organisation. 

After the Money In The Bank 2011 PPV, Punk went into negotiation with WWE after leaving with the WWE Title. He eventually signed a 3 year deal with them and everything worked out for both parties.

However, July 2011 + 3 years = July 2014 = Contract Expiring.

2014 is seemingly now a big year for CM Punk (and fans) whether he will renew his contract or not. WWE Payback is going to be based in Chicago this year which potentially could be the last time he wrestles for WWE in his home town making that PPV potentially a lot bigger than it first seemed. 

Within the last year, there has been speculation whether Punk will retire after this latest run given his injuries and reports he is just tired. There's also been several visual elements to Punk's fatigue at times seeing large bags under his eyes or tweaks within his injuries during matches.

Will CM Punk be in WWE by the end of the year? We'd like to think so but the clock is ticking.