DENVER (AP) — Atlanta closer Jason Grilli ruptured his left Achilles' tendon while tumbling to the ground Saturday, the Braves announced in a tweet after the game.

Grilli suffered the injury as he ran toward first to cover the base on Drew Stubbs grounder to first to begin the ninth inning. The Braves pitcher is expected to miss the rest of the season.

He was sprinting to cover the bag when he appeared to take a bad step and crumpled to the ground, grabbing his lower left leg in pain. Stubbs was safe on what was ruled a hit.

Team trainers and manager Fredi Gonzalez ran on to the field to tend to Grilli, who remained on the ground for several minutes. He was helped to his feet and taken away for further treatment on a cart.

The Braves lost 3-2.