GLENDALE, Ariz. -- Throughout organized team activities and minicamp, Arizona Cardinals coach Bruce Arians often talked about the depth inside the wide receivers room. He liked to say the Cardinals had 12 receivers who were capable of playing in the NFL.

His tune changed Monday.

“Not very pleased with our wide receiver room,” Arians said. “Must’ve been seeing things back in the spring when I said we had 12 guys that could play in the NFL.”

His new estimate? Two NFL-caliber receivers: Larry Fitzgerald and Jaron Brown.

He then issued a warning shot across the bow.

“We’ll look around [and] see who’s available,” Arians said.

Arians cited the receivers' play as a major reason for the offense’s “lethargic” practice. They ran the wrong assignments, missed cutoff blocks on the back side, and dropped too many passes -- the two core responsibilities of a receiver, Arians pointed out. Arians said Monday’s practice was a carryover from last week, when the receivers struggled, as well.

Brown, who Arians declared has been playing “as good as you can get,” said Arians’ message was “loud and clear.” Brown said that “stupid mental errors” have been a common occurrence recently.

“It wasn’t our best day but we have to come out here tomorrow and have a better day,” he said.

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Receiver J.J. Nelson said any mistakes by receivers in the Cardinals’ offense are magnified.

“It’s pretty noticeable,” Nelson said. “That’s one thing about this offense is it’s pretty noticeable because everything ties in together, so if one guy messes it up, you mess up the whole play. So that’s why they always tell us we got to be in tune with each other.”

The only offensive players Arians was pleased with were the quarterbacks. Otherwise, the collective, including tight ends, disappointed all day.

On top of that, the amount of time that receiver John Brown’s quad injury has caused him to miss has started to become an issue for the Cardinals.

“It’s a concern,” Arians said. “He’s not available. You’re only as good when you’re available.”