Several things to point out.
1. The Jags have a very strong run defense, one of the best in the NFL.
2. The offensive line was not giving DD many chances.
3. DD has never been a feature back, he has always been a situational back.
He needs to improve.
Running back may be #1 on the priority list for the Texans draft next season.
It is impossible to keep your eyes open when you sneeze.