Smith's left foot got stepped on during a pass-protection drill on Wednesday. He went for tests that detected a broken bone in the foot -- the same one that he broke last season as a rookie.
Coach Marvin Lewis revealed the test results after practice on Thursday and said it's unclear whether Smith will need surgery. Dennis Roland will replace Smith at right tackle for Sunday's game at Indianapolis (5-3).
Bengals quarterback Carson Palmer says he's returning to practice on a limited basis, going easy on his sore passing shoulder. Palmer hurt the right shoulder when he was sacked during a 27-21 loss to Pittsburgh on Monday night.
The Bengals held Palmer out of practice on Wednesday, giving the shoulder time to recover. He expected to participate in some of practice on Thursday, but the shoulder was still sore and he was held out again.
He expects to play against the Colts.
"I'm definitely going to go, but (I'm) just getting a couple days of rest on it," Palmer said.
Smith was the sixth overall pick out of Alabama last season. He missed most of training camp in a holdout last season, then broke the foot in practice two days later, sidelining him for most of the season. He played in six games last year with one start.
He had surgery on the broken bone in the offseason, and was out of shape when he reported for training camp, drawing Lewis' wrath. Smith got into shape and had started the last three games.
Lewis said the latest fracture is in a different bone in the foot. Smith might have surgery to repair the new break and also treat the older one.
"It's the bone next to (the old injury), which will be good because they never really felt good about the last procedure being totally and completely mended," Lewis said. "So now there is a chance to go back and, if that's the course of action, to go back and re-fix the original one and then fix this one."
Smith and Roland have shared time at right tackle the last two seasons. Roland, a former college free agent, started 12 games last season. He also was the starter this year while Smith got into shape.
Lewis pulled Smith from the loss to the Steelers after he gave up a sack in the third quarter. Roland replaced him briefly, but Smith went back in and finished the game. The Bengals gave up four sacks overall.
Palmer hurt his shoulder on one of the sacks, but stayed in the game and threw the ball well. He hit Terrell Owens with a pair of touchdowns and leading a final drive that ended at the Pittsburgh 12-yard line in the closing seconds.
"He said, 'I'm still a little bit sore and let me not stretch it out too bad yet and then get ready to go tomorrow,"' Lewis said. "But yeah, the plan was for him to go today."
Lewis said that Palmer will start Sunday in Indianapolis even if he doesn't practice on Friday. Palmer was confident the shoulder will be good enough to let him play against the Colts. His brother, Jordan, is the backup.
The loss to Pittsburgh dropped the defending AFC North champions to 2-6, scuttling their season. They have several players restricted in practice this week because of injuries, including defensive lineman Tank Johnson, who has a knee injury.
Copyright 2010 by The Associated Press