I don’t know what games you’ve been watching but Roberts has had several good returns this season.
Now, today, he made a couple mistakes in running the ball out of the end zone on kickoffs. A touchback puts you at the 25 yard line. These days, returners rarely get there on kickoff returns out of the end zone. What we don’t know is if he was directed to do that or did it on his own. Usually the returners stand at the goal line and let the ball go if over their head.