Source: The Wrestling Observer
At this is time, one of the plans going around is for CM Punk to feud with Brock Lesnar when he returns to WWE TV. According to reports, when Punk returns, Paul Heyman would turn on him to help set up the feud.
The feeling is that with his return, Punk will easily get babyface reactions. Also, the feeling with Lesnar is that he is built for heel run while he is back with WWE. The two could face off as soon as SummerSlam, but could be pushed all the way back to Survivor Series.