Who will start in Palmer's absence is uncertain.
Matt Leinart took over after Palmer was knocked out of the game by the Panthers but struggled in his first extensive playing time this season. He completed 16 of 32 attempts for 115 yards, had several passes sail out of bounds and threw a costly interception just before halftime.
Terrelle Pryor made a brief appearance against Carolina and caught a 22-yard pass from Palmer after originally taking the snap and throwing to Palmer behind the line of scrimmage. Pryor was also in on two plays near the goal line, running for 2 yards and passing for 5.
"We'll get both those guys reps in practice with the first team this week," coach Dennis Allen said Monday. "We're not ready to make that decision. We'll see how practice goes, and later in the week we'll be ready to name a starter."
That's a 180-degree turn from Allen's stance after the 17-6 loss to Carolina when he told reporters that Leinart would be the team's No. 2 quarterback behind Palmer. He also said of Pryor -- a third-round pick in the 2011 supplemental draft and the final player selected by former team owner Al Davis -- that "we don't feel like he's ready to be the backup quarterback just yet."
Leinart certainly didn't do much to help his own standing, which might be why the Oakland coach is mulling a change.
The 10th overall pick in 2006, Leinart looked rusty while completing only 50 per cent of his throws. Oakland drove down into the red zone twice with him at quarterback but settled for field goals both times. Leinart also threw an interception into triple coverage just before halftime with the Raiders trailing 7-3, and the Panthers converted the turnover into a touchdown that broke the game open.
"I think he would tell you there were some plays out there that we left on the table," Allen said of Leinart. "We expect him as well as anybody to make those plays. But some of it obviously has to do with getting rushed (in) and not getting an opportunity to play a lot."
With the exception of two plays, Pryor spent the second half on the sideline.
Oakland fans repeatedly have chanted Pryor's name during home games this season and general manager Reggie McKenzie has said he wants to see Pryor play to further evaluate the quarterback's abilities.
That could happen if Allen decides to give Pryor his first NFL start next Sunday in San Diego.
"I don't know that he's got full command of everything that we're doing but I wouldn't expect a lot different out of any other young QB," Allen said. "We'll work him this week in practice (and) make a decision at the end of the week which way we want to go."
Following the loss to Carolina, Pryor told reporters he would be ready to go if he was the starter against San Diego.
"I definitely don't make decisions like that," Pryor said. "I just go out and do my job. Whatever God has for me, it's going to happen. If not, I'll be fine."
Palmer was hit in the back by Hardy late in the first quarter while rolling out to throw. Hardy appeared to lead with his helmet and drew an unnecessary roughness penalty, one of six such penalties accumulated by the two teams combined.
Palmer was later taken to a hospital in Carolina and underwent a CT scan which revealed the cracked ribs and bruised lung. Palmer was able to rejoin his teammates for the flight home, but upon arrival in Oakland the quarterback was transported from the plane to Eden Medical Center in nearby Castro Valley and kept overnight.
A Raiders spokesman said Palmer was released from the hospital Monday afternoon.
"He made the flight back home with us but spent the night overnight in a hospital for observation," Allen said. "He'll be out this week."
Notes: Right guard Mike Brisiel suffered a concussion against Carolina. ... Safety Tyvon Branch (ankle) and cornerback/punt returner Phillip Adams (groin) were also hurt in the game. ... Allen said the team might look at moving outside linebacker Miles Burris to the middle in the off-season. Burris, a fourth-round pick who has started 14 games as a rookie this season, led the Raiders in tackles against Carolina and also got his first NFL interception.