X-rays were negative, but general manager Marty Hurney was uncertain how long the four-time Pro Bowl receiver will be out. Smith was injured when he got tangled with cornerback Chris Gamble early in the evening workout, held without pads.
This injury doesn't appear to be as serious, but could keep Smith out for a while.
Smith crumpled to the turf and grabbed his right arm after a slight collision with Gamble in a passing drill. He took off his helmet and kicked it before walking to a nearby tent, favoring his right shoulder.
Smith was briefly treated before being carted inside, where he underwent X-rays. It wasn't immediately clear if Smith would be taken to Charlotte to be further evaluated.
Smith had 78 catches for 1,421 yards and six touchdowns last season and is the top target of quarterback Jake Delhomme. Smith, who turned 30 earlier this year, is Carolina's franchise leader with 51 touchdown catches.
The Panthers have little proven depth behind him. The other starter is 36-year-old Muhsin Muhammad. Dwayne Jarrett, who has caught 16 passes in his first two seasons, is the leading candidate to be the No. 3 receiver this season.
Copyright 2009 by The Associated Press