Harris has a shot especially if Peterson isn't around. However, much like the Vikings' WR move, I'm left scratching my head on this one. At WR they jettisoned a possession receiver in Jennings to get a pure speedster in Wallace. They already had speed.
With DuJuan Harris at RB, it's not much different than McKinnon. They are similar backs and of similar potential, maybe giving more of a nod to McKinnon since he's only entering his second year. Harris sure isn't a bruising back like Asiata, so I'm not sure what value Harris adds to the Vikings.
This move strikes me as a Frank Walker / Marquand Manual free agent move. You're just adding a body to the roster without much hope that they will be a solid contributor.