Oakland Raiders receiver Antonio Brown lost his grievance with the NFL on Monday over his use of an old helmet that is no longer certified as safe to use for practice or play.

The arbitrator issued the ruling after holding a hearing last Friday with Brown, representatives from the league, and the players’ union.

‘‘While I disagree with the arbitrator’s decision, I'm working on getting back to full health and looking forward to rejoining my teammates on the field,’’ Brown said in a statement on Twitter. ‘‘I'm excited about this season appreciate all the concerns about my feet.’’

Brown has not participated in a full practice for the Raiders after starting training camp on the non-football injury list with injuries to his feet that reportedly came from frostbite suffered while getting cryotherapy treatment in France. Brown was cleared to practice July 28 and participated in part of two sessions but wasn’t around the team last week when he had the grievance hearing with the NFL over his helmet.

The National Operating Committee on Standards for Athletic Equipment sets performance and test standards for equipment. Brown’s Schutt Air Advantage helmet is no longer allowed because the NFL follows the National Athletic Equipment Reconditioners Association rule that helmets 10 years or older cannot be recertified.


Schutt discontinued making the helmet three years ago because current technology had moved past it, according to the company.

Brown was one of 32 players using helmets last season that are now banned by the league and players’ association. Those players, including Tom Brady, were able to use the helmets last season under a grace period but were required to make the change in 2019.

Raiders CB suspended

Raiders cornerback Nevin Lawson was suspended four games for violating the NFL’s policy on performance-enhancing substances.

The league announced the decision Monday, one week after Lawson revealed he had tested positive for Ostarine despite ‘‘never knowingly’’ taking the substance.


Lawson will be allowed to participate in the preseason and training camp practices. He will be eligible to play in the regular season after the Week 4 game at Indianapolis.

Lawson, who is in the mix for one of the backup spots, signed a one-year deal in March after spending the past five seasons with the Lions.

Browns’ Thomas suffers scare

Browns defensive end Chad Thomas sustained a sprained neck but avoided a more serious injury during a scary moment at training camp.

Thomas was immobilized on the field and taken by ambulance to University Hospitals.

A team spokesman said Thomas, a third-round pick in 2018, was back at the Browns’ facility Monday evening. His return to practice will be evaluated on a day-to-day basis.

Thomas appeared to absorb a blow to his right shoulder and head during a play. The 6-foot-5-inch, 280-pounder stood up but then went to the ground, where he was treated by Browns medical personnel.

As his teammates and fans at camp watched somberly, Thomas was put on a backboard and carted away.

Thomas appeared in four games for the Browns last season. He’s expected to be in Cleveland’s defensive line rotation this season.

Jets have trouble on corner

The Jets have quite a conundrum at cornerback. Injuries are piling up at a position that wasn’t very deep to begin with, and Adam Gase is relegated to trying to put a positive spin on things rather than simply panic.


‘‘This is a great opportunity for a lot of guys,’’ Gase said Monday after an injury-filled practice. ‘‘Somebody has a chance to step up and make a name for themselves.’’

Top cornerback Trumaine Johnson is the biggest name and most experienced of the Jets cornerbacks, but he is sidelined indefinitely with a hamstring injury suffered in practice Sunday. Johnson was being counted on to have a bounceback season after injuries and inconsistency resulted in a down first season with New York.

But, he might not take the field again for a while. He had an MRI on his hamstring, and Gase didn’t sound optimistic.

‘‘That’s just going to be time,’’ Gase said. ‘‘I don’t think it'll be months, but, I mean, we'll see. We’re going to be week-to-week right now.”

On Monday, the starting cornerbacks were: Darryl Roberts, mostly a backup during his first four NFL seasons; veteran Brian Poole, whose role will be primarily as the nickel corner; and undrafted rookie Kyron Brown, who has looked promising while rising up the ever-changing depth chart.

But Brown, from Akron, left practice with a hamstring issue of his own after chasing down Robby Anderson during drills. He clutched the back of his left leg before leaving the field with a trainer.

Arthur Maulet, who spent the last two seasons with the Saints and Colts, joined the starters on defense after Brown went out.