The former middleweight champion twice tested positive for the anabolic steroid Drostanolone before and after his UFC 183 victory over Nick Diaz in January.
Pettis started idolising Silva after the Brazilian defended his middleweight championship by demolishing Rich Franklin at UFC 77 in 2007.
While many people were skeptical when Silva claimed that he had no idea how he failed numerous drug tests, Pettis believes that his idol is telling the truth.
"I just can't see him consenting to cheating," Pettis told mmafighting.com on Wednesday. "I don't think that's something he would do. I mean, when you're at that high of a level, people want to see you back, there's money to be made if he fights again, so somebody had to be in his ear or somebody had to be giving him stuff that he didn't know what it was. I hope he had no idea what it was.
"People in [Silva's] camp, his doctors … I think they probably didn't tell him the truth about what he was taking and that happened. It happens in every sport."
With Pettis now waiting to see what happens to Silva, he has denounced the Brazilian's critics who say that his 16-match winning streak as middleweight champion from 2006 to 2012 will forever bear a black mark.
Pettis also pointed out that Silva couldn't have cheated during that period of time since he never failed a drug test.
"I mean, that's a guy, you can't take away what he's done for the sport for one mistake that maybe he didn't even make," Pettis said. "The casual fans (are doing that), you know? Like, ‘oh, he's been cheating his whole career.' They have no idea, watching him in the UFC when it was just his first fight, they don't know what it takes to get where he's at. So people are so quick and easy to judge, and nobody knows what's going on."