"He's all in. Ready to go," Gruden told reporters, according to Vic Tafur of The Athletic.
Brown donned a Schutt Vengeance Z10 LTD, which is among the NFL's 34 approved helmets, a source told Ian Rapoport of NFL Network.
The development comes after Brown reportedly filed a second grievance against the league Monday in an effort to wear his preferred Schutt AiR Advantage helmet, which is banned by the NFL due to safety standards.
The hearing in front of an arbitrator will likely take place Friday, according to Rapoport.
Gruden added that he doesn't believe Brown's injured feet will be an issue going forward.
"I'm confident that he's going to be a heck of a player for us and be ready to roll," the coach said.