ALAMEDA, Calif. — 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 on 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.

NFL spokesman Brian McCarthy earlier in the day reiterated the league’s stance that Brown wouldn’t be allowed to practice or play without a certified helmet.

• Oakland Raiders cornerback Nevin Lawson has been 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 signed a one-year deal with the Raiders in March after spending the past five seasons with the Detroit Lions. He was in the mix for one of the backup spots at cornerback for Oakland this season.

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.

GIANTS: Saquon Barkley has no problem watching preseason games from the sidelines, if that’s what Coach Pat Shurmur wants.

While in uniform, the NFL offensive rookie of the year last season was a spectator and cheerleader for the Giants’ 31-22 victory over the Jets on Thursday.

Speaking to the media Monday after practice, Barkley shrugged off his role as a non-participant. He is getting a lot of work every day in practice. He’s been a halfback long enough to know how to run the ball. And he certainly doesn’t need to get hit to get ready for the season opener at Dallas on Sept. 8.

If last season is any indication, the second pick overall is going to be hit around 400 times this season. He carried the ball 261 times for 1,307 yards and was targeted for passes 121 times, catching 91. That’s 382 times he was a target and doesn’t take into account either the times he has to block or when he is hit while carrying out a fake.

VIKINGS: Minnesota hired Toronto Blue Jays executive Andrew Miller as chief operating officer.