Brown's agent, Drew Rosenhaus, responded Sunday night to Raiders general manager Mike Mayock's statement that the team has "exhausted all avenues of relief" for Brown's equipment-related grievance.
"I'm not sure that we agree that we've exhausted all the options, as Mike Mayock said, but there's no doubt it's still an ongoing process," Rosenhaus said on 7 Sports Xtra.
"We are trying to work with the team and the league and the union to come up with a solution. We haven't figured it out, yet," Rosenhaus continued.
Brown found his preferred Schutt Air Advantage helmet that was manufactured within the past 10 years but it failed NFL testing.
Two more helmets have been found and are being tested for possible use, according to NFL Network's Ian Rapoport.