The receiver's two-game suspension for breaking teammate Ken Lucas' nose in a training camp fight ended Monday morning.
He was seen leaving Bank of America Stadium around noon carrying two cardboard boxes and joking with defensive tackle Damione Lewis.
Smith did not speak to reporters.
"He's ready to roll," coach John Fox said. "Obviously he's excited to be back and excited that we're 2-0."
The Panthers insist they have gotten over the hard feelings created by Smith's sucker punch in camp. Smith slugged Lucas during a break in practice Aug. 1 while Lucas was on one knee with his helmet off.
The next day the Panthers suspended their three-time Pro Bowl selection without pay for the first two regular-season games. Smith apologized to the team a day after that, and Lucas said he accepted his apology.
Without their top playmaker, the Panthers stunned San Diego on Jake Delhomme's 14-yard touchdown pass to Dante Rosario as time expired in the season opener. On Sunday, the Panthers scored the game's final 17 points to knock off Chicago 20-17 for their first 2-0 start in five years.
The Panthers have until Wednesday to clear a roster spot for Smith, who has been on the reserve-suspended list. Carolina visits 0-2 Minnesota next Sunday.