Olsen suffered a broken right foot in Week 2 against Buffalo a year ago and missed nine games after having surgery. He returned for the final five regular-season games and playoff loss to New Orleans.
Olsen returned to the sideline in the second half on crutches with a walking boot on his right foot, the same one he injured a year ago. The injury happened when Olsen stepped on a defender's foot.
Coach Ron Rivera said he had no update on Olsen's injury other than to say it was the same foot that Olsen injured a year ago. Olsen politely declined to comment.
Olsen, 33, in April signed a two-year extension through the 2020 season. He was a late addition to the injury report on Saturday with a stiff back, but he was able to start.
Olsen, the first tight end in NFL history to have three consecutive 1,000-yard receiving seasons (2014-16), had two catches for 33 yards before leaving the game.
In other injuries, Panthers right tackle Daryl Williams left the field on a golf cart for the second time since training camp opened. He went down with 8 minutes, 38 seconds left in the opener with what the team called a knee injury, apparently to the same knee where Williams suffered a torn MCL and dislocated his right patella early in camp.
Rivera said Williams' knee injury was not related to his first injury, but he didn't elaborate on how serious it was.
After the game, the tone from teammates seemed to indicate Olsen will be out a while.
"You guys know how I feel about Greg,'' quarterback Cam Newton said. "You can't ever replace him. Just his professionalism he brings to this game and his overall outlook and IQ, understanding. But in a way [rookie] Ian [Thomas] has been preparing for this moment. . . . I'm just going to leave it up to the front office to see who they bring up next or not or we just do with what we have.''
Said center Ryan Kalil on Olsen, his good friend off the field, "I'm sick to my stomach for him.''
"We've got to move on,'' Kalil added. "We've got to see who is going to take over that spot. We've got to adapt. We've got a long season to go.''