The Ravens first lost their quarterback. Then they lost their bite on defense.

By the end of yesterday's deflating 23-21 loss to the Carolina Panthers, the Ravens had lost something they had built all season long.

Hello, bye week. Goodbye, momentum.

Lapses on offense in the first half and breakdowns on defense in the second half snowballed into the Ravens' second straight loss and two weeks of second-guessing.

"Our momentum has taken a hit," said tight end Todd Heap, whose face - a bloody bandage over the bridge of his nose - symbolized the beaten-up state of the team. "We started off on a roll and we have hit a little dip. Sitting for two weeks with the taste of a loss in your mouth is not going to be fun. Hopefully, we can all reflect and figure out what we need to do to get better as a team."

Starting quarterback Steve McNair was lost on the Ravens' third series of the game, suffering a medium concussion and a neck sprain. All tests on his head and neck were negative. He was released from Union Memorial Hospital.

Although Ravens officials said the team would wait to determine his status for its next game (Oct. 29 at New Orleans), teammates said they expect McNair to be able to make that start.

The Ravens (4-2), who remained a half game ahead of the Cincinnati Bengals in the AFC North, can only hope the rest of the team will show up for an entire game, too.

"As a team, you've got to pull something like that out, somehow, someway," said receiver Derrick Mason, who was held without a catch for the first time since 2002. "It's over with. I'll see you all in two weeks. I'm going to rest and [to heck] with football right now."

In a game that ended the Ravens' six-game winning streak at M&T Bank Stadium, the Ravens essentially had momentum on their side for a matter of seconds.

One play after the Ravens cut the fourth-quarter deficit to 16-14 on Kyle Boller's 62-yard touchdown pass to Mark Clayton, the Panthers struck back with a 72-yard pass from Jake Delhomme to a wide-open Steve Smith, quickly silencing the largest crowd in Ravens history (70,762).

A blunder in the Ravens' secondary - cornerback Samari Rolle let Smith run free because he thought safety Ed Reed had coverage for the deep middle part of the field - allowed the Panthers to push their lead to 23-14 with 4:15 left in the game.

"He was my responsibility and he scored a touchdown. It was a miscommunication," Reed said. "We knew what they were going to do and they made a play."

The Ravens did respond with a 7-yard touchdown from Boller to Heap, cutting the margin to 23-21 with 2:13 remaining. But Carolina converted on third-and-one when Delhomme hit Drew Carter for 4 yards, and the Panthers (4-2) ran out the remaining seconds for their fourth victory in a row.

"I was hoping that we would get one more opportunity to get the ball in our hands," Heap said. "And it was frustrating that we didn't get that one more opportunity because I had a good feeling that if we got the ball, we'd go down and score. It just didn't work out for us."

The Ravens' defense made two defiant stands in the red zone but failed at other critical times.

The NFL's second-ranked defense allowed 414 yards (its most since Dec. 5, 2004, against Cincinnati) and a season high in points. The Panthers also converted on seven of 15 third downs (47 percent) after going 0-for-11 last week against Cleveland.

"Carolina is a good group, but they're not as good as we made them out to be today," cornerback Chris McAlister said.

The Panthers' bull's-eye was squarely on Rolle. Carolina threw 11 passes at him, completing eight of them for 171 yards and two touchdowns.