UFC President Dana White was caught by TMZ cameras recently and asked about Brock Lesnar's eventual return to the sport of MMA. He noted that because of his illness Brock went out on a low note and "feels like he wasn't 100%", and that he definitely wants to return to the company.
When asked if he would rather do wrestling or fighting, Dana said "I think he wants to do both" and mentioned that he would welcome the former Heavyweight Champion back with open arms.
There has been a lot of talk recently about Brock Lesnar potentially returning to the UFC, but it isn't likely that he could do both at the same time. While Dana White has been open in the past that he feels the two companies are completely different products, it isn't likely that the WWE would let one of their top stars work for a company they feel is competition. Plus, the physical stress both jobs put on an athlete could interfere – if Lesnar were to injure himself in a match, or in an MMA fight, he'd be a liability to both companies.
At this time, Brock is signed with the WWE through WrestleMania 31 in 2015.