Smith missed the regular-season finale against the Atlanta Falcons after suffering a left knee sprain a week earlier against New Orleans. He has spent the past two weeks, including a bye week in the opening round of the playoffs, rehabbing.
"It's not about, 'Can I go?'" Carolina's all-time leading receiver said Monday. "It's how confident do I feel when I am going? I will play Sunday. It's about how much of that do I don't worry about the knee. That's when the confidence increases."
Panthers coach Ron Rivera said all are expected to be on the field Wednesday when Carolina (12-4) begins game planning for the 49ers, who advanced with a 23-20 victory Sunday over the Green Bay Packers.
Rivera expects each player to be available for Sunday.
But getting Smith back is more crucial than the others because of what he brings to a passing game that has struggled without him. Rivera said there is an element of simply having Smith on the field that helps Carolina.
"What is Steve going to do? What can Steve do? How can he impact the game?" Rivera said. "That can only be answered by once you get on the field and how are they [49ers] going to approach Steve.
"I do love Steve's enthusiasm. I do love who Steve is. You can't duplicate that. He's a special guy. Steve will find a way to be effective and make things happen."
Smith finished the regular season second on the team in catches with 64 for 745 yards and four touchdowns. For his career, he has 836 catches for 12,197 yards and 67 touchdowns.
Smith led the team with six catches for 63 yards in a 10-9 victory over San Francisco at Candlestick Park on Nov. 10.
"I did a good job today, so we're going to see how tomorrow goes and I'll be practicing on Wednesday," Smith said. "Just got to build up that muscle memory. Had that fluid [in the knee]. The injury caused some kind of trauma in there, so just trying to work through that.
"I should be fine for Sunday, though."