CHARLOTTE, N.C. (AP) -- Panthers wide receiver Steve Smith said Thursday his injured left knee isn't coming along quite as well as he'd hoped.
Smith practiced for the second straight day on a limited basis, saying, "It didn't feel as great as I thought it'd feel."
He said he "overdid it a little" in practice.
Smith estimates he's "57 percent" healthy, down from 71 percent he mentioned on Wednesday.
As for whether he'll play Sunday against the 49ers in the NFC divisional playoffs, Smith said "I'll have to see" on Friday.
Coach Ron Rivera expressed some concern, saying Smith didn't look as sharp Thursday in practice as he normally does.
"When you watch Steve and watch the way he does things, there's a smoothness to his movements and stuff -- and it's not quite there yet," Rivera said.
Smith said the primary issue is his cutting ability while running routes.
"I'll be all right," he said. "I'm going to need some treatment."
At 34, Smith remains an integral part of Carolina's offense.
The franchise's all-time leader in receptions, yards receiving and touchdowns finished the season with 64 catches for 745 yards and four touchdowns. He's also valuable in that he often requires double coverage, thus opening up things for other receivers as well as the team's running backs.
He's also the only wide receiver on the Carolina roster with any significant playoff experience.
In eight postseason games, Smith has 47 receptions for 782 yards receiving and seven touchdowns and has played in a Super Bowl. He's also run for one score and returned a punt for another touchdown in the postseason.
Smith had six catches for 63 yards in Carolina's 10-9 win over the 49ers on Nov. 10 in San Francisco.
Smith's problems began when he sprained his posterior cruciate ligament while running a route in the first quarter of Carolina's Week 16 game against New Orleans. He returned for one play but then left again and did not return, limping off the field and into the locker room.
He sat out the following game against Atlanta and had hoped that with a first-round bye he would return to form for the playoffs.
Rivera said Thursday "there's always a chance" that Smith doesn't play Sunday and the team has contingency plans in case he's unable to play.
"He's not his normal self yet, but he was out there," Rivera said. "He did things he was supposed to do. We'll see how he feels tomorrow. He came in and felt a little sore" after practice.
The Panthers are more optimistic about getting running back Jonathan Stewart back on the field Sunday.
Stewart, who has missed the last three games with a torn ligament in his knee, said he's feeling stronger and expects to play against the 49ers.
"I definitely have a burst, and rehab was good to me," Stewart said.
But he also said he's not pain-free.
"Pain is something I'll have to deal with," Stewart said.
Stewart said he felt fortunate that he didn't tear his ACL, which would have ended his season, and required surgery and months of intense rehabilitation. He said he won't need surgery to repair the existing tear.
Stewart has only played in six games this season for the Panthers after missing the first seven games with an ankle injury. He has run for 180 yards on 48 carries this season.
AP NFL website: www.pro32.ap.org