Mason has quietly established himself as one of the league's most solid pure runners, accomplishing the uncommon feat of averaging 5.1 yards per carry over his first 395 rushing attempts. That's especially tough to pull off as a power back who mostly works between the tackles -- some runners juice their rushing average with timely if not lucky chunk gains on draws or in situations where the defense isn't ready for the run, but Mason earns his yardage with the defense squared up. There are at least two significant hurdles limiting Mason's upside all the same: the first is that Mason hasn't gotten many chances as a receiver, drawing only 34 targets on 947 snaps (82.4 percent catch rate, 5.1 YPT), and the second is that Mason has shown a fumbling tendency the last two years, dropping the ball six times on just 337 touches from scrimmage. Mason's otherwise standout running ability rapidly loses its usefulness when he's fumbling, and if he continues to fumble roughly once every 50 touches, he'll likely lose playing time at some point. In the meantime, veteran Aaron Jones is probably diminished enough as a runner for Mason to remain the Vikings' preferred runner between the tackles, though Jones will likely take the passing downs and in-space touches.