The running back has already amassed 100 carries for 342 yards this season, scoring one touchdown.
Sullivan told the NFC South side's website: "He is [being utilised heavily], and we're aware of that and I think again he'll probably be the first person to say, 'I want more, I want more'.
"Any time we can get him into open space where he has the ball in his hands and the closest defenders are [yards away], as opposed to him having to hit a tight crease, that's advantage us and advantage him.
"I feel very comfortable and very confident with where we're at after the bye week, having really taken a hard look at what we need to do to fix our problems."
Tampa Bay play the Philadelphia Eagles this Sunday.