The backup running back was placed on the Reserve/Did Not Report list Saturday after failing to show for the start of training camp.
Mason did not participate in Los Angeles' offseason program. Coach Jeff Fisher attributed his absence to "personal reasons."
The 22-year-old tailback was arrested in March on drug and traffic charges and has had five separate incidents with police over the past four months. Fisher acknowledged in June that the Rams "have to prepare ourselves that Tre's not going to be here."
Fisher revealed Saturday that Mason has broken off communications with the team:
TMZ Sports reported earlier this week that Mason's family is "extremely concerned" about his mental health, citing a "string of bizarre behavior and angry outbursts."
Mason was viewed as a nucleus player on the Rams offense after earning a spot on the 2014 All-Rookie team. Reduced to a sidekick role following the addition of franchise back Todd Gurley, Mason managed a disappointing 2.8 yards per on 75 carries last season.
While it's fair to wonder if the Rams will cut ties with Mason, his personal well-being is the chief concern.
