Zac Stacy is expected to play on Sunday for the St. Louis Rams against the San Francisco 49ers.

Stacy is coming back from a concussion in last week's game.

Stacy has 624 yards on 141 carries and four touchdowns.

Zac Stacy had 127 yards on 27 carries with two touchdowns, along with another six catches for 51 yards receiving in the St. Louis Rams' 28-21 loss to the Tennessee Titans.

Stacy has clearly emerged as the Rams' lead back.

“From the moment that Zac Stacy took over that No. 1 spot he’s been a great weapon for us,” quarterback Kellen Clemens said. “He’s a good back. He’s also very good out of the backfield. He’s a great weapon for us. We’re lucky to have him. He’s stepped up in a big way.”

“Zac Stacy is a heck of a back,” end Chris Long said. “If he can stay healthy and continue to improve, he’s going to make people’s lives pretty tough. He’s a tough runner, he gets a lot of yards after contact.”