LOS ANGELES -- Former UFC heavyweight champion Brock Lesnar, now a star in the WWE, was cageside at UFC 184 on Saturday, prompting speculation that the big man is on his way back to the UFC.

Lesnar is nearing the end of his contract with the WWE and there has been talk, though none of it from Lesnar, that he wants to return to mixed martial arts. Lesnar suffered from diverticulitis during his UFC career and was never fully healthy.

After defeating Antonio Silva in Porto Alegre, Brazil, on Sunday, one-time Lesnar rival Frank Mir called Lesnar out and said he'd love a rubber match.

UFC president Dana White smiled when asked about Lesnar's presence during the event and said, "I don't know [why he's here.]" Lesnar was not available to media. On Thursday, Dave Meltzer of the Wrestling Observer and MMA Fighting reported that Lesnar had come to a contract impasse with the WWE.