BOSTON (CBS) — In the first quarter of Sunday’s game between the Eagles and Patriots in Philadelphia, Tom Brady and the Patriots offense took the field for the first time. On the TV broadcast, Jim Nantz and Tony Romo were on screen, discussing what they expected to see out of the New England offense after their bye week.

As the camera cut to Brady breaking the huddle, loud boos began to take over the broadcast. The sound of that booing then elevated rather abruptly.

Such a spike could have been the result of some audio mixing on the broadcast, but according to 98.5 The Sports Hub color commentator Scott Zolak, the unnatural rise in volume was heard in the stadium.

“Sounds like noise is being pumped in, doesn’t it?” Zolak asked play-by-play announcer Bob Socci.

“Got a little louder there, didn’t it?” Socci replied.

“That just got turned up!” Zolak said. “Oh. Oh my!”

During Monday’s Zolak & Bertrand show, Zolak said that the spike in volume did not happen again for the rest of the game, but something was definitely suspicious about that initial bump in boo volume.

“Something spiked mid-call to make me say that. Bob heard it, too, because I looked right over at him before I said it, and he looked at me,” Zolak said. “And it was like someone just put their finger on a thing, and it went right up. Because it was a quick jump. That wasn’t a slow, ‘Let’s get the crowd up here, ohhh, everybody’s going [crazy], put the noise meter on the board.’ No, that was a quick spike right there.”

Low quality video, but here is the spike in crowd noise that @scottzolak said sounded unnatural as Tom Brady broke the Patriots huddle for the first time in Philadelphia yesterday. pic.twitter.com/wo0mTLNIgz — Michael Hurley (@michaelFhurley) November 18, 2019

A former NFL quarterback and an experienced broadcaster, Zolak has been in just about every NFL stadium that’s existed over the past 30 years, so his perspective on the matter is notable.

“That was the first time it ever happened in seven years [in the booth] where I noticed that,” he said. “Something was noticeable right there at the beginning. That was the first drive. … That’s home-field advantage. I didn’t think about it the rest of the game, but something spiked mid-call.”

In his weekly radio appearance on WEEI, Brady was asked if he noticed any volume spikes.

“Good job, Zo. I like it,” Brady replied. “I didn’t notice. But those are not things that I would notice. Loud is loud. I mean, at one point, you can’t hear basically … it’s like loud, and then louder, but you’re not gonna notice the difference much. Once it’s at a point where we have non-verbal communication, then it kind of is what it is.”

Suspicion of illegally pumping in crowd noise is nothing new to the NFL. The Colts were accused — but cleared — of doing it in in 2007 (something that Brady still doesn’t buy). The Falcons were busted for amplifying crowd noise in 2015, a violation that cost them a fifth-round pick and a $350,000 fine.