ORCHARD PARK, N.Y. — Cam Newton's answers were short, and plain, and honest.

The reality for the Panthers offense at the moment is just as harsh.

After another day in which they were unable to move the ball down the field, the Panthers are staring at an uncertain final three games — and an offseason which will require significant work.

Asked what was wrong with the passing game after a 31-14 loss to the Bills, Newton didn't blink.

"I don't know," he replied.

Asked later what the most frustrating part for him at the moment was, and he was just as direct.

"Not winning," Newton said.

The Panthers have lost four in a row, all of them since Newton's dramatic return in the goal-line package at Arizona.

The streak started with his best game, an exceptional performance against Washington. That day, Newton was 21-of-27 for 189 yards, with two touchdowns, for a 120.5 passer rating.

In the three games since, he's 38-of-82 for 426 yards, with a touchdown and four interceptions, for a combined passer rating of 46.0.

While Newton's persona and charisma and the back of his football card make him an easy thing to focus on, the current streak is not all his fault by any stretch of the imagination.

The Panthers are still out there without Christian McCaffrey, and they're still struggling to protect any quarterback. Newton was sacked four times, behind a starting offensive line which was the 10th different combination in 14 games. Few of them have been sufficient to sustain a passing game, with none of the three quarterbacks who have played this season enjoying much in the way of time for things to develop.

Sunday, Newton averaged 4.1 yards per pass attempt (18-of-38 for 156 yards), which wasn't the Panthers' lowest such number of the season. That came in New Jersey against the Giants (3.72), the day Sam Darnold was benched.

"Certainly right now, our passing down the field is not one of our strengths," Panthers head coach Matt Rhule said.

That's not particular to Newton, either.

"I don't think the whole year we had too much of a vertical game, I wouldn't say just the last four or five weeks," wide receiver Robby Anderson said.

Sunday didn't feature the kind of "catastrophic" turnovers that have undermined the Panthers in recent weeks, but several moments underscored the larger themes.

In a scoreless first quarter, they lined up for a fourth-and-1 play at the 50 — because Rhule said the plan was to be aggressive in those situations anyway.

But when Newton came away from center, and the Bills were blitzing, his bubble screen pass to Anderson was off-target, perhaps the result of him trying to throw it to a place where a Bills cornerback wasn't going to pick it off.

"It's a zone-read play. It shouldn't be thrown," Rhule said. "It's a zone read. There's a bubble on there in case an unblocked blitzer comes. That's just an error by the quarterback. It should be a handoff first down, or he pulls the ball (down and runs it himself)."

Asked if that was a function of Newton still not being up to speed with the playbook, Rhule replied: "It wasn't done right. It wasn't executed. I mean, I can't sit here and say why. He saw the guy blitz, you can throw the bubble off the blitz, but we have that guy blocked. It should be handed off."

Then, midway through the second quarter, Newton underthrew an open DJ Moore on a deep ball that could have turned into a touchdown.

Again, putting all the blame on Newton for the game wouldn't be fair. He was sacked four times, he led the team with 15 carries for 71 yards and a touchdown, and his playmaking ability kept things interesting into the fourth quarter, when his touchdown pass to Ameer Abdullah cut the gap to 24-14. That 23-yard catch and run was the Panthers' longest pass play of the day.

The offense did move the ball well at times — enough to keep backup quarterback P.J. Walker on the bench — but never consistently enough.

"I think it was just a matter of, we were moving the ball really by running the quarterback," Rhule said of the decision not to play Walker. "I think we had 151 yards rushing today. I thought that was our best chance to move the football was to run the quarterback and continue the zone reads and some of those things."

It's not a particularly satisfying answer, considering the loss was their fourth straight and ninth in the last 11. So when Rhule was asked about the possibility of another change at quarterback, he said he didn't want to make any global declarations in the moments after a difficult loss.

"I think that dynamic element to our offense is certainly missing," Rhule said. "We have to work really hard for everything that we get, and that would certainly help, but in terms of who's playing quarterback, nothing right now."