He missed much of last season after suffering a concussion.
Girma Berkessa says in the complaint that an "extremely intoxicated" Oher pushed him to the ground, kicked him and called him a homophobic slur several times April 14.
"The brain is a scary thing", Oher tweeted after the news of his release broke.
On Thursday, Rivera said Michael's health always came first, especially when making such a decision.
Oher's eight-season, 110-game National Football League career began with Baltimore in 2009.
In 2016, Oher started the first three games of the season before a concussion caused him to be inactive for the next seven games and placed on injured reserve. "Michael understood and we expressed that to him", Rivera continued. The film was nominated for an Academy Award in the Best Picture category and Sandra Bullock won the Oscar for Best Actress for her portrayal of Oher's adoptive mother.
The 31-year old tackle was a big component of the Panthers' 15-1 season in 2015, as he started all 16 games for them at left tackle, and he had three years remaining on his contract after having been extended by the Panthers last season.
Oher was a member of the 2012 Ravens Super Bowl team.
After spending one year with the Titans, Oher joined the Panthers in 2015 and played an integral part in the team's NFC championship.