Jefferson started to come on strong at the end of the offseason program, Tim Twentyman of the Lions' official site reports.
Jefferson apparently was most impressive in the passing game, and it sounds like he has distanced himself from Michael Warren and Dedrick Mills for the Lions' No. 3 running back job ahead of training camp. However, it's hard to imagine that the seventh-round rookie will be challenging D'Andre Swift or Jamaal Williams for a significant role with the first-team offense anytime soon.