Nonetheless, Foster is expected to get the majority of carries against the Bucs after becoming the first Carolina back to break the 100-yard barrier this season.
"I don't get into starting lineups at this point in the week," Fox said. "We'll announce that when the time is right."
Davis was held to 8 yards on five carries Sunday, but Fox insists the 31-year old back still has a role with the team. What that role is, however, remains a mystery.
"Yes. They all have a role in our running back rotations," Fox said. "Each week, games take on different personalities, and we try to use our players that are going to give us the best chance to win. They are all a little bit different."
One of the reasons Foster and Davis have been able to co-exist in the backfield is because they have a close friendship and remain very supportive of each other.
When Foster scored his first touchdown of the season on Sunday on an 18-yard reception from Jake Delhomme, Davis sprinted across the field to congratulate him in the end zone and then ran back across the field to the sidelines before the extra point.
"They are both outstanding people as well as football players," Fox said. "I think they've cheered each other on since they've both been at the position. That's not changed because maybe some of the carries have changed of late. I have tremendous respect for both of them and how they handle it. They are very selfless and they care about winning."
Asked if that's an unusual occurrence, Fox said, "I don't know that it's unusual, but it doesn't always happen like that. Sometimes people are s little more selfish than selfless. But I think it's unique and I think it's important in winning."