With the running game under the spotlight, one running back began Thursday’s game in the starting lineup and left with a concussion. Another had started training camp atop the depth chart and now hopes he can survive the final roster cutdown Saturday.

Redskins Coach Mike Shanahan said rookie Evan Royster, who started Thursday against Tampa Bay and played most of the first half, suffered a mild concussion. Royster finished with 44 yards on 11 carries with a one-yard touchdown and a costly fumble.

With Tim Hightower sitting out Thursday’s game, Ryan Torain came off the bench and saw his first action of the preseason. He had 73 yards on 17 carries, most in the second half. He’ll now wait until Saturday to see if that was enough.

“I felt like I showed a lot. ...I’m never comfortable until the coaches let me know I’m on the roster,” said Torain, who missed the previous three games with a broken left hand. “I’m excited.”

Shanahan opted to also sit rookie Roy Helu, which seems to indicate that Hightower and Helu could start the regular season comfortably on the depth chart. Coaches will decide Saturday whether they’ve seen enough of Torain to give him a significant role.