McClain, 26, had 80 tackles, two sacks and an interception in 11 games (all starts) for Dallas last season. He was suspended for the first four games last season for the same violations.
It’s the latest blow for a defense that also will be without defensive ends Randy Gregory and DeMarcus Lawrence for the first four games of the upcoming season — also because of violations of the league’s substance abuse policy. ESPN reports Lawrence’s appeal was denied Thursday.
Also, Cowboys DE DeMarcus Lawrence's appeal was denied, he is suspended 4 games, per @toddarcher.