Speaking on Wednesday, Saints coach Sean Payton characterized the trade as an obvious move for both teams.
"This was done just using common sense, and we had a chance to get a draft pick next year," Payton said, via Josh Katzenstein of The Times-Picayune. "I know Arizona was short at this position, and there's a confidence level we have with how Mark and how Alvin are playing."
The Saints signed Peterson to a two-year, $7 million contract before the draft. After trading up to select Kamara in the third round just days later, the question became how New Orleans would juggle the three running backs.
In the end, Peterson became the odd man out.
Despite All Day carrying just 27 times for 81 yards through four games and spending the majority of his time on the sideline, Payton said he still believes Peterson can be a productive runner.
"In my discussions yesterday with (Cardinals general manager) Steve Keim, it was like, 'Hey, this guy still has it, and here's what he does well and we've seen it,'" Payton said. "it's just a little crowded right now."
Despite Peterson's outward appearances of frustration with his role in New Orleans, Payton said neither side harbors ill will.
"Our relationship, I would say, has been fantastic, and (the trade) was an opportunity really where he was going to obviously get somewhere and be featured more, and I'm happy that that opportunity has come up and we were able to make a trade," Payton said.
Trading Peterson frees up a better running back rotation in New Orleans. Ingram can continue as the early down runner and Kamara a dynamic change-of-pace pass-catcher out of the backfield. Had the Saints known they were going to snag Kamara in the draft and he'd turn out to be a pivotal piece out of the gate, it's likely the Saints would have never signed Peterson.