Stewart has been recovering from a sprained knee suffered in a Dec. 8 game at New Orleans. He was inactive the last three regular-season games but practiced all week prior to Sunday's contest.
Panthers coach Ron Rivera said Friday that he still was looking for Stewart to show that explosive burst before deciding whether to activate him.
Carolina wide receiver Steve Smith, as he said all week, will play against San Francisco. Smith missed the regular-season finale against Atlanta after suffering a sprained knee in a Dec. 22 game against New Orleans.
The team's all-time leading receiver, Smith said earlier in the week he was physically fine but just trying to get through the mental aspects of working through the injury. Without Smith at Atlanta, Carolina wide receivers had four catches for 22 yards.
Niners cornerback Carlos Rogers also was inactive Sunday due to a hamstring injury.