Brown, who didn't practice with the team Tuesday, was away from camp due to frostbitten feet after failing to wear proper footwear in a cryogenic therapy chamber. He also filed a grievance against the NFL over wearing his old helmet.
"I'm extremely grateful to be here," Brown told reporters. "Been dealing with a lot of adversity, but it's on the up and up. I'm excited to be back, see my teammates, and get in the groove of things here shortly."
Brown's helmet grievance was denied Monday, according to ESPN and the NFL Network. He accepted the independent arbitrator's decision to uphold the ban on him using his 10-year-old Schutt Air Advantage helmet, but now the receiver is searching for a newer model of the same helmet.
Before arriving at Tuesday's practice, Brown posted on social media asking fans for help in locating a newer version of his old helmet. The All-Pro wideout said he would trade an autographed practice-worn helmet for a 2010 Schutt Air Advantage model.
Brown and his agent, Drew Rosenhaus, said they located some of the helmets, according to ESPN.
"We're working with the NFL in regards to the helmet," Brown said. "I'll be making sure I put on the right equipment-approved helmet and be ready to go shortly."
If Brown acquires a model that's been manufactured since 2010, the helmet must be reconditioned and re-certified by the National Athletic Equipment Reconditioners Association, according to ESPN. Due to the outdated technology, it remains unclear whether the NFL would sign off on the helmet if it's certified.
Brown's Air Advantage model was discontinued in 2009 and is no longer certified by the National Operating Committee for Standards and Athletic Equipment. NFL and NOCSAE policies prohibit the use of helmets that are older than 10 years.
Schutt continued to produce the helmet in 2010 to ensure a supply of parts for reconditioning and any warranty claims, according to ESPN. A 2010 Air Advantage Model would be allowed for use if approved by the league.