Romo stepped forward in the pocket and escaped pressure to his left while Avril closed from Romo’s backside. Romo began to slide as Avril chased him down and was caught in an awkward position as the two players went to the ground.
Romo immediately reached for his lower back area and was tended to be the Cowboys’ training staff being walking off the field under his own power.
Dak Prescott replaced Romo at quarterback upon his exit from the game.
Romo has not left the Cowboys sideline and is throwing passes during Seattle’s opening possession.
Romo completed his only pass – an 11-yard slant to Terrence Williams – before being hurt on the third snap of the game.
UPDATE 10:40 p.m. ET: Romo has not returned to the game and multiple on-field reporters have said it’s a coach’s decision to keep him on the sidelines.