Sporting News' Vinnie Iyer previews NFL training camp with a look at the eight key rookie vs. veteran running back battles around the league. What will be the roles of Clyde Edwards-Helaire, D'Andre Swift and Jonathan Taylor? Why is A.J. .Dillon gaining steam and Ke'Shawn Vaughn losing some?Here's updating the status of the competitions with a look at how they all might play out leading into Week 1 of the 2020 regular season. Learn more about your ad choices. Visit podcastchoices.com/adchoices