"There's a time and a place -- I'm not saying specific to what comments were made -- there's a time and place for things like that," McDermott said. "This was not one of them. We have a lot of respect for our opponents, No. 1, and everyone in the league. I've spoken with Kelvin, and that's not how I want us to handle things like that. So we'll move forward as a team, and I'm hoping we've already done that."
Benjamin told The Athletic in a Q&A after practice on Friday that he and the Panthers were never a good fit, and he lamented that he wasn't able to play with a more accurate quarterback than Cam Newton to begin his career.
Panthers quarterback Cam Newton appeared to answer Benjamin in a video posted via his Instagram story.
"Hey, I ain't going to go back and forth with him. I'm just going to work. You feel me? That's all it is, you know what it is. Just work, baby," Newton said in the video while walking on a treadmill.
At Panthers training camp, Newton was not made available to reporters despite requests to talk to him. But early in practice, at the beginning of a passing drill, he seemed to take a shot at Benjamin, though he didn't mention the receiver's name.
"Think I'm a liability,'' he said. "I think I'm an asset.''
Panthers coach Ron Rivera wouldn't address Benjamin's comments, "just because he's not one of our players.''
"I'll talk about our players and what we have here,'' he said. "It's time to move on.''
Benjamin said Sunday that he has no plans to reach out to Newton to clear the air.
"No, man, I'm just moving on. I'm just moving on," he said.
The Bills host the Panthers on Thursday at New Era Field in both teams' preseason opener.
"That's a part of it, but the bigger part of it is our focus needs to be on what we're doing," McDermott said Sunday. "Like I said, we respect what they do, every opponent -- everyone in the league, for that matter -- but the bigger part is our focus needs to be on us and our approach to training camp."
"I echo what Sean [McDermott] said," Bills GM Brandon Beane said Monday. "We spoke to Kelvin and we wish he hadn't handled it that way. He understands and I don't think you'll see that from him going forward."
Newton posted a 58.5 completion percentage in Benjamin's first season in 2014, 59.8 in 2015, 52.9 in 2016 and 59.1 last season. He has cracked 60 percent just twice in his career: 60 percent in 2011, his rookie season, and 61.7 percent in 2013. He has a career completion percentage of 58.5.
Benjamin answered those critical of his comments in a tweet Saturday, writing that he has been "holding it all in. And now I'm free. Hate me or love me."
He said Sunday that his comments were made in "the heat of the moment."
"I was just angry at the time. It just came out," he said, adding that he is "going to learn from it."
He said he has no problem with McDermott's comments Sunday "because he's right."
"That can be a distraction for the team, and I don't want to be no distraction to my team, so like I said, man, I'm moving on from that. I said what I had to say, and I'm just focusing on the team right now," he said.
ESPN's David Newton contributed to this report.