ESPN's Ryan Clark and Herm Edwards agree with Panthers quarterback Cam Newton's assertion that he is not getting the calls that other quarterbacks get. (1:24)

Newton not officiated the same as other QBs (1:24)

The NFL has concluded that officials should have penalized the Arizona Cardinals for an illegal hit Sunday on Carolina Panthers quarterback Cam Newton, a league source told ESPN's Ed Werder.

The play in question, which Newton complained about after Carolina's 30-20 victory, was a low hit by Arizona defensive lineman Calais Campbell, who dove at the reigning league MVP and hit him low while he was in the pocket.

Newton acknowledged Sunday that late hits like the one from Campbell are "taking the fun out of the game for me" and said he wants to speak with NFL commissioner Roger Goodell about the issue.

Panthers coach Ron Rivera said that he has had ongoing discussions with Goodell, although he would not reveal how recently he had talked with the commissioner. But a league source told Werder that Rivera spoke to Goodell and at least two other league executives Monday.

Goodell promised Rivera in their conversation Monday, the source told Werder, that he would speak directly to Newton, who also expressed concerns that "I don't even feel safe" while playing. A high-ranking Panthers source told Werder that Newton and Goodell did speak Tuesday, but it was not clear what was discussed.

Panthers general manager Dave Gettleman also spoke to the league office Monday about his concern for protecting Newton, according to the source.

Opponents haven't received a roughing-the-passer penalty against Newton this season, except for one that was offset by an intentional grounding penalty in the season opener at Denver. This is despite Newton being hit an NFL-high 212 times during that span.

Rivera said the 6-foot-5, 260-pound Newton gets treated like Hall of Fame NBA center Shaquille O'Neal because of his unusually large size for his position.

"He's a bigger guy for that position, as opposed to some of the smaller guys,'' Rivera said Monday. "When they get hit, they roll around to the ground. When he gets hit, he absorbs them and it doesn't look as bad.

"I think sometimes that might be part of the reason that he doesn't get the calls he deserves or should get.''

Some around the league, including Pittsburgh Steelers offensive lineman Marcus Gilbert, do not agree that Newton is treated unfairly.

Gilbert, citing teammate Ben Roethlisberger, said Monday that larger quarterbacks should "embrace" the sport's physicality just like other players and suggested that Newton should have the Panthers change their game plan if he doesn't want to get hit.

Hall of Fame pass-rusher Kevin Greene, who spent three seasons with the Panthers, also weighed in Tuesday.

"That's just football," Greene said. "You never saw Joe Montana and Dan Marino and John Elway bitching about getting hit too much in the pocket.

"Cam shouldn't be doing that. He is a football player. Everybody knows he's running that zone-read stuff, and he's a runner, too. ... The game is physical. It's played by tough men. This is professional football and it's predicated on physical brutality. That's going to occur to you, Cam, whether you're inside the pocket or outside the pocket."

ESPN Panthers reporter David Newton contributed to this report.