Is Brock Lesnar Leaving the UFC to Go Back to WWE?

Rumor has it that Brock Lesnar is thinking about leaving the UFC to go back to the WWE. After a very disappointing one sided loss to Cain Velasquez, it seems Lesnar would rather do Wrestlemania than fight again. Since Brock has one of the biggest draws to the UFC, he could be using this as leverage to get more money out of the UFC.
Possibly a good move considering he is on the final fight of his UFC contract. If Lesnar leaves the UFC he is going to fuel the fire of him being a quitter and not going after the Heavyweight Championship Belt. Hopefully he trains harder and makes a comeback.

Brock Lesnar quitting UFC for WWE?