EAGAN, Minn. -- Vikings coach Mike Zimmer is not backing down from an allegation that further confuses the NFL's officiating approach this season.

On Zimmer's Wednesday radio appearance on KFAN's "X's and O's," he was asked about roughing the passer calls and the perceived ambiguity about how those plays are officiated. Zimmer noted the difficulty the new rules create for defenders in making legal tackles and then pivoted to bring up a play in which safety Andrew Sendejo was flagged 15 yards for his hit on Packers receiver Davante Adams.

"It's very difficult for a defender -- really playing defense, nowadays. The official actually said to Sendejo on his hit," Zimmer said on KFAN. "[Sendejo] said, 'What could I have done different?' [The official] said, 'You did everything right. You couldn't have done anything different. They just want us to throw the flag.'"

Zimmer did not question officials about the incident during the game because he said he was not made aware of the alleged interaction until a day later.

"Well, I couldn't do anything at the time," Zimmer said Thursday. "I didn't find out until Monday."

Zimmer said on KFAN that he called the league office for clarification. As of Thursday, the Vikings coach said he had not received a response from the NFL.

Michael Signora, the NFL's vice president of football communications, told ESPN the league does not have a comment on the matter.

The play in question took place with 8 minutes, 4 seconds remaining in the third quarter. Packers quarterback Aaron Rodgers launched a 16-yard pass that was caught by Adams, who was initially tackled by Xavier Rhodes. Adams appears to lower his head upon being brought down by the cornerback before being hit by Sendejo.

On video, it appears that Sendejo aimed to lead with his right shoulder but caught the side of Adams' helmet with his own. The penalty called was in protection of a defenseless receiver, not the helmet rule that has come under fire this season.