Trey Potts averaged 6.4 yards / carry last year. He may well turn out to be better than Mo with far less wear and tear on his joints. He's not a 'second string' running back.
Behind him you have Cam Wiley, who averaged 6.2 yards / carry last year.
Behind him you have Bryce Williams, who averaged 4.3 yards / carry as a true freshman in 2018. We haven't seen him play meaningful snaps since he was a serviceable B1G running back at 18 years old _three years ago_
Behind him you have Ky Thomas, who is widely viewed as the _most_ talented RB on the roster.
Minnesota is going to have a solid running attack as long as the offensive line stays healthy. They will be able to run on any team, all season long, as long as the offensive line holds up.