NFL: Julius Thomas call correct

— -- TEMPE, Ariz. -- The officiating crew in Denver made the right call when it flagged Denver Broncos tight end Julius Thomas for chop blocking Arizona Cardinals defensive end Calais Campbell, the league said Monday.

Campbell suffered a Grade 2 MCL sprain on the play, Cardinals general manager Steve Keim said Monday morning on his weekly radio show.

On the play, Campbell was rushing off the right edge and Broncos left tackle Ryan Clady stood in a pass block stance but had yet to make contact with Campbell. At the snap, Thomas, who was lined up next to Clady, dove into Campbell's knees for the chop, causing the injury and forcing Campbell to miss most of the second half.

"The play was penalized because it was an illegal chop block, a violation of Rule 12, Section 2, Article 3 items c) and d)," NFL spokesman Michael Signora said. "The officials threw the flag for the 'reverse chop.' Thomas blocked Campbell 'in the area of the thigh or lower,' as specified by rule, and Clady engages Campbell high 'simultaneously or immediately after the block' by Thomas, resulting in the penalty.

"The play also violated part c) of the rule, known as a 'lure.' While Thomas chops Campbell, Clady 'confronts the defensive player in a pass-blocking posture but is not physically engaged with the defensive player.'"

Signora said a potential fine for Thomas could be handed down later this week.

"Cut blocking is allowed in the National Football League. It is utilized by everybody in the league, but you cannot have the tackle engage and cut block at the same time, but that in no way was intentional, never been coached by me or anybody on my staff or any player we have on our football team," Broncos coach John Fox said Monday. " ... I believe that's our first chop block called in our tenure here in our four years. It was a look we had not seen much of."

After the game, Cardinals coach Bruce Arians was livid about the play.

"I've been coaching for 37 years, and it's the dirtiest play I've ever seen in the National Football League," Arians said. "It was a flat chop block that put him out of the game. I've never seen anything like it. I know [Broncos coach] John Fox, and he's a great coach and a great guy. Somebody has got to answer to that.

"A fine isn't going to do it when [Campbell is] going to miss three to four weeks on a blatant chop block."

Thomas defended himself when told about Arians' comments and said that he sought out Antonio Cromartie to have the Cardinals cornerback deliver a message to Campbell.

"I don't spend much time worried about what others think of myself or what should happen. You can spend all day with all the opinions of any play of any game, or what others think," Thomas said Monday. "I'm not going to pay too much attention to what he feels should happen."

"The main thing is there was no intention for anybody to be hurt on the play and hopefully he'll be back soon," Thomas added.

Veteran wide receiver Larry Fitzgerald was equally as unhappy about the play.

"It was bulls---," Fitzgerald said before catching himself. "It was terrible, man.

"We all saw it. We lose our defensive captain, and the guy [Thomas] goes out to catch two more touchdowns in the game. I felt like he should've been thrown out of the game. That could've been a career-ending injury. We obviously lost [Campbell] for the game. We don't know how long he's going to be down. That was a big turning point in the game."

Fox said he spoke to Arians after the game.

"Calais was lined up at end and he spends most of his time down inside, it was a three-man rush that we didn't communicate as well as we'd like," Fox said. "I never like to see any player injured ... it costs us a 77-yard touchdown so we're not coaching that."

"I talked to [Arians] after the game," Fox added. "... It's not the dirtiest play I've seen this year, let alone 35 years."

The Cardinals lost seven players due to injury in Sunday's loss, and one of them -- starting outside linebacker Matt Shaughnessy -- will go on injured reserve designated to return. Shaughnessy, who has knee cartilage damage, cannot play in a game for eight weeks, meaning he could come back for the final four games of the season.

ESPN.com Broncos reporter Jeff Legwold and The Associated Press contributed to this report.