Cam Newton has expressed his frustration about what he feels is the NFL’s failure to provide him with protection on the field.

Newton’s father had spoken out earlier in the season after the Carolina Panthers quarterback had taken several helmet-to-helmet hits, for which opposition defenders were not penalized. On Sunday, Cam Newton was incensed when Arizona Cardinals defensive tackle smashed into the quarterback’s knees but was not punished.

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“Enough is enough,” Newton said after Carolina’s 30-20 win over Arizona on Sunday. “I don’t think there’s a person that can go through what I go through and keep their head, you know what I’m saying? Hits to the head, that’s one thing, but when you’re not protected in the pocket, that’s another thing. It became the story of my life ever since I came in [to the league]. It’s always, ‘Oh, we missed that, I’m sorry.’ That’s bull crap.”

Newton said he intends to talk to the NFL commissioner, Roger Goodell about his treatment. “I just can’t keep accepting, ‘Oh, we missed that one,’ or ‘I apologize for doing that’ or ‘I didn’t see it.’” Newton said. “That’s horse crap. Coming from a person who’s been fined before, coming from a person who everybody’s expecting a lot from, I’m still going. But yet, when you constantly see the hits, when you constantly see flags being picked up and flags not being thrown, and to see other quarterbacks getting it for lesser physical hits, it’s taking the fun for me out. I’m just being honest about that.”

Newton was not the only person complaining about a lack of protection on Sunday. The Kansas City Chiefs quarterback Alex Smith had to leave the field twice after taking hits to the head in his team’s game against the Indianapolis Colts. On one occasion the Colts safety Clayton Geathers pushed Smith’s head into the turf and was not punished.

Dov Kleiman (@NFL_DovKleiman) #Chiefs Alex Smith got hit hard in the head twice today, went to Locker room after both, here's the first pic.twitter.com/ixLBxpOIRg

That led Smith’s wife, Elizabeth, to speak out: “How many hits does he have to take before a flag is thrown,” she wrote on Twitter. “Funny when some QB’s gets tapped flags go flying.”