Chael Sonnen appears to be in Boxing Hall of Fame trainer Freddie Roach's corner on Juan Manuel Marquez's physique.

Sonnen on Wednesday took aim at the WBO light-welterweight champion, who earlier this month knocked out star Manny Pacquiao, saying he "miraculously went through puberty a second time" before the fight.

The UFC light-heavyweight contender never directly accused Marquez of taking a performance-enhancing drug, but he cast suspicion on the fighter given a "visual test."

"The guy's got a six-pack that he never had before," Sonnen said on Showtime's "Jim Rome: Live." "There are two tests that you have. You've got the pee test, but you've also got the visual test.

"When you take your robe off and you get in the ring, that's the first test. And to act as though all of us didn't go, 'Something's going on, there.'"

As backup, Sonnen, who's skills as a raconteur have won him a commentating job with FUEL TV, cited Roach's comment to USA TODAY Sports in which he said if Marquez was clean, he would "kiss his ass."

"Did he take something? Sure, he did," Sonnen said. "Did he take something illegal? Well, according to the (drug) test, no."

"The Ultimate Fighter 17" coach, who's set to face opposing coach and light-heavyweight champ Jon Jones in April, knows quite a bit about that subject. He ran afoul of the California State Athletic Commission in 2010 over his use of prescribed testosterone, for which he was suspended following a failed title bid against Anderson Silva at UFC 117. (He appealed separate punishments for the infraction, claiming he properly disclosed his use.) Prior to a rematch with Silva at UFC 148, he applied for and received a therapeutic-use exemption to use the hormone, which opened him to regular out-of-competition testing.

Marquez, who avenged a pair of losses and a draw to Pacquiao with his brutal sixth-round KO, sternly denied Roach's implication in interviews prior to the Dec. 8 fight and said he was open to extra testing. Pacquiao, who once settled out of court with star Floyd Mayweather Jr. over unproven steroid allegations, echoed that willingness but sidestepped accusations. (Both fighters passed post-fight drug tests the Nevada State Athletic Commission oversaw.)

Angel Hernandez, the strength and conditioning coach who once testified about his role in the BALCO scandal and later took a role as Marquez's strength and conditioning coach for the third Pacquiao bout, suggested his fighter's accusers might be scared of a fourth meeting. He said fighters working with him were required to undergo random drug testing.