Manager Don Wakamatsu said Tuesday before a game against the Chicago White Sox that his only consistent home run threat started feeling tightness in his lower back before Monday's game. Branyan then felt it more running on a double in his first at-bat that night. He left after his second at-bat.
Casey Kotchman again replaced Branyan at designated hitter Tuesday.
Branyan has 13 home runs and 34 RBIs in 65 games for Cleveland and Seattle. The Mariners acquired him in a trade late last month.
Wakamatsu also said left-handed starter Erik Bedard was due to have a team doctor read another MRI exam of his ailing shoulder.
Bedard had been set to make his season debut early this month following shoulder surgery in August, but more pain derailed that plan.