One of the more underrated aspects of the Colts' playoff run last year was the production they got from their running back position, as Dan "Boom" Herron took over for Trent Richardson and played a key role for the team.
Herron played in all 19 games for the Colts last year (including playoffs) and started six, including each of the last five (including the three playoff games). On the season, he rushed for 521 yards and 3 touchdowns while averaging 4.2 yards per carry and also added 41 receptions for 301 yards in the passing game, averaging 7.3 yards per catch. His season started off slowly, as he saw just eight carries over the first six games combined, and through the first ten games he had received just 22 carries on the season. Herron had been relegated to the third running back role behind Trent Richardson and Ahmad Bradshaw, but Bradshaw was injured in week eleven against the Patriots, and with Richardson still not producing, Herron began to see an increased role. After getting just 22 carries through the first ten games, Herron saw 101 carries over the last nine games and played a key role in the offense. He couldn't replace the production of Bradshaw (who was having a terrific season until he was injured), but Herron at least gave the Colts a threat out of the backfield that Richardson absolutely didn't.
There was some question about what role Boom Herron would have in 2015, but it seemed pretty clear that he had at least earned a spot in the running back picture for the team. The Colts signed Frank Gore in the offseason to be their starter, and sixth round draft pick Josh Robinson could see some playing time, as could Vick Ballard if he stays healthy. But at this point, it seems like Herron is still the number two running back, and he should do a solid job there - particularly when paired with Frank Gore. Herron showed good skills as a receiving back in 2014 and someone who Andrew Luck trusted with dump-off passes, and he could be used in the same way this year.