Fournette missed Weeks 4 and 6 with an ankle injury and played only one snap in Week 5.
"He's good to go," Arians said. "He's practiced full. He'll reassume his role. He's ready to go."
Fournette serves as a change-of-pace back for starter Ronald Jones II, contributing in the screen game and wearing the opponent out in the fourth quarter. In four games this season, Fournette has averaged 5.1 yards per touch and has contributed 157 scrimmage yards (123 rushing).
He was originally expected to be active for last Sunday's game against the Green Bay Packers, but he was scratched after the team saw something during warmups that gave them concern.
"There was no sense in risking him tweaking it and losing him for another month -- just get him healthy," Arians said. "I feel very confident about the other three guys. RoJo is handling the load really [well], Ke'Shawn [Vaughn] is coming around and Shady [LeSean McCoy] is doing his job. Just get him healthy. We'll need him down the stretch for sure.
"It's a long season. His best interest is what I'm concerned about [and] our best interest. We're going to need him."
Fournette was initially frustrated by the decision to sit out last week's game, but he posted Monday on Twitter that "the young immature me would of been upset but now I understand coach he cares for his players first."