Is Brock Lesnar preparing for a return to MMA? UFC president Dana White isn't ruling it out.

"Brock Lesnar's under contract with the WWE. We have a great relationship with him," said White, speaking at a "UFC: The Time Is Now" press conference in Las Vegas earlier this week. "He's healthy and he has said that he's interested in fighting again. We'll see what happens."

Lesnar left UFC to join the WWE in 2011, following back-to-back losses to end his career. His contract with WWE runs until 2015, at which point he'll be able to reenter the octagon if he so pleases.

UFC Champ Could Lose Title If He Doesn't Fight Soon

Should he return, Lesnar will no doubt immediately be a major tentpole attraction for the sport. Here are three potential challengers for his hypothetical comeback fight.

Frank Mir

Lesnar's UFC 100 headliner with Frank Mir still holds the record for most pay per view buys ever, with 1.6 million. A rematch between the two, coupled with the general hype of Lesnar's return, would give that figure a run for its money.

Cain Velasquez

The current champ was supposed to headline a title defense at UFC 180 against Fabricio Werdum, but an MCL injury saw him replaced by Mark Hunt. Dana White has gone on record as saying Velasquez needs to fight in spring 2015 in order to retain his title...which'll be just around the time Lesnar's WWE contract runs out.

Antonio Silva

This Brazilian fighter last fought in September 2014, so the calendar might not match up with Lesnar's. However, Silva is one the sport's most consistent figures and a headliner between him and Lesnar would no doubt be a treat to witness.