Khan is preparing to regain his world titles but Peterson believes that the British boxer is one-dimensional in his approach to fights.
The American said: "He'll do what he always does, he always fights the same.
"He's either straight forward or straight back. That's the way he fights, he's not going to change it.
"He's still out there saying he's the champ, but he's not. He's all over the place. Really, I don't know what to make of him."
Peterson defeated Khan on a split decision last December in Washington DC.