Derrick Henry and Saquon Barkley among veterans eager to see how the NFL values running backs

NASHVILLE, Tenn. (AP) — Derrick Henry is back in the gym, eager to prove turning 30 is just a number that shouldn’t affect the four-time Pro Bowl running back’s value on the NFL’s open market. The man who organized a group chat among the league’s top running backs last summer is about to find out exactly what teams are willing to pay for proven experience. And Henry has company with stars such as Saquon Barkley, Josh Jacobs and Tony Pollard — the three running backs hit with franchise tags in 20