Now Adrian Peterson sits a few lockers away from the injured young star.
"It was a humbling moment just because he's one of the idols," Johnson said. "It's going to be cool to pick his brain and learn from him."
The respect is mutual.
Peterson, who has Johnson's injury to thank for him landing in Arizona, said he likes Johnson.
"He came in and had an incredible career so far with what they've asked him to do here," Peterson said. "Humble guy. Down to Earth. Hard worker -- that's all I've heard about him. Just the opportunities I've had to talk to him were brief."
Johnson and Peterson talked in Minnesota once before, and Peterson congratulated Johnson "on the things that he had accomplished so far."
Johnson told Peterson he's trying to be like the former NFL MVP.
"I've always looked up to Adrian Peterson," Johnson said. "He's one of the guys I grew up watching just because he's Midwest. He played for the Vikings so it's cool to have him on the team, as well."
Johnson is looking forward to watch Peterson up close, "see what he's thinking," what his mentality is in games and certain situations.
Peterson doesn't mind. Johnson once told Peterson he paved the way for backs like Johnson.
"I sit back and marvel and just smile (when) I hear young guys like that say how I influenced them and their play and their work ethic," Peterson said.