CHARLOTTE, N.C. — The sharply managed marketing of Cam Newton has been under way for a while, with a stylish cover shot for GQ last summer, a deal with Under Armour and a recently announced clothing line available only at Belk department stores, a Southern chain.

But Newton, the Carolina quarterback, is having a hard time living up to the branding. After being the N.F.L. offensive rookie of the year last season, Newton is struggling, pouting at times and grasping for answers as the Panthers, who viewed themselves as playoff contenders going into the season, have lost five of their first six games.

"The past couple of games have been the same script, by the same director,” Newton said after a 19-14 loss to the Dallas Cowboys on Sunday. "It’s kind of getting boring. This taste, this vibe — I’m not buying it, man. And I don’t know what it is, but something’s going to have to change. Something’s going to have to change real fast.”

On Monday, it did. The Panthers fired Marty Hurney, their general manager for 10 years, the man who made Newton the No. 1 overall pick in the 2011 draft. His dismissal increased the pressure already felt by the second-year coach Ron Rivera and his staff.

And by Newton.

After being fired, Hurney — without singling out Newton — told reporters that there needed to be stronger leadership in the Panthers’ locker room.

"I think Marty hit the nail on the head when he said that,” Newton said Wednesday. "I think everybody has to take that challenge and be better at what we do and more consistent.”

Still, Newton acknowledged, "1-5 is extremely harder to lead than 5-1.”

Newton’s leadership has been questioned more than once since his arrival here. He was criticized by teammates for sulking on the sideline during losses last season, when the Panthers went 6-10. After being replaced by Derek Anderson in the final minute of a 36-7 loss to the Giants on Sept. 20, Newton drew the anger of the veteran leader Steve Smith as Newton sat on the bench.

"I lit into him because I thought it was an opportunity for him to see and understand what was going on,” Smith said then. "This is more than about playing football. It’s about becoming a man and understanding what this is.”

Whatever impact that had on Newton, it has not translated to the field. Newton, a 6-foot-5, 245-pound force who became the first rookie to pass for more than 4,000 yards, and the first quarterback to rush for 14 touchdowns in a season, is not nearly as dominating this season.

He has rushed for a team-best 273 yards, but just three touchdowns. And Newton has thrown for 1,387 yards — 26th in the league — with just five touchdowns and six interceptions. That includes a second-quarter interception in the end zone in the loss that sealed Hurney’s fate Sunday.

That was hardly Newton’s only ugly outing. There was a 16-10 season-opening loss at Tampa Bay, in which Newton was intercepted twice and rushed for 4 yards. He reassured fans the next week, by passing for 253 yards and a touchdown and rushing for 71 yards and another score in a 35-27 victory over New Orleans.

But the debacle against the Giants in the third game began a four-game losing streak. Now Newton is the 23rd-ranked quarterback in the N.F.L., just behind Seattle’s rookie, Russell Wilson.

"He’s had an up-and-down year,” Rivera said of Newton. "He’s done some really good things. He’s struggled with some other things. And again, it’s not just about him. This is a team game. Part of it’s about what we’ve done schematically. Part of the things that we’ve tried to do to stay ahead of the curve, we may have gotten too far out there.

"I think part of it is, really, teams have adapted to us as well. Last year we were a bit of an unknown quantity. This year we’re a little bit more known.”

Of course, it also comes down to execution. The Panthers have lost four games by 6 points or fewer, failing to make big plays with the game in the balance.

"I think we’ve had so many games that came down to the last drive where it’s causing me to get gray hair,” Newton said. "It’s so many things that we can point and say this and say that. Well, it comes down to, I won’t even say leaders leading. We’re beyond that point. We’re to the point now that, players gonna have to play.”