FOXBOROUGH, Mass. -- While Oakland Raiders wide receiver Antonio Brown says he won't play football unless he can wear his old helmet that is now banned by the NFL, New England Patriots quarterback Tom Brady acknowledged that it's been an adjustment for him to get used to a new helmet.

"I've been experimenting with a couple different ones, and I don't really love the one that I'm in, but I don't really have much of a choice," Brady said Monday on the "The Greg Hill Show" on sports radio WEEI. "So I'm just trying to do the best I can to work with it."

Brady's old helmet, the Riddell VSR-4, was among those prohibited by the NFL this year, as part of a joint venture with the players' association to help improve player safety.

Brady previously said he understands the reason for the change, even as he struggles to adapt to it.

"You get used to the same helmet for a long period of time. My last helmet, I wore it the last four Super Bowls, so it was a pretty great helmet for me. I hated to put it on the shelf," he said on the radio program. "It's kind of what I'm dealing with."

NFL spokesman Brian McCarthy noted that NFL policy states that helmets have to be certified by the National Operating Committee on Standards for Athletic Equipment (NOCSAE) and that it doesn't clear equipment that is older than 10 years.

McCarthy explained that players can't practice or play in games until they wear an approved helmet.

For the first 15 years of his career, Jason Witten wore two Air Advantage helmets by Schutt affectionately known as Betsy. When he opted to return to the Cowboys this year after one-year in ESPN's "Monday Night Football," booth, he knew he could no longer wear Betsy because the Air Advantage had been phased out. Since the start of organized team activities in May, he has worn a Vicis helmet.

"It's been a long time coming, so I knew like anybody, the rules are the rules so you've got to evolve with them," Witten said. "There's a lot of things you'd like to change, but at the same time you've got to evolve. It's been a pretty easy transition. As much as I loved that helmet, I knew some things were out of my control and that was one of them."

ESPN's Todd Archer contributed to this report.