Redskins' running back Evan Royster rushes against the Bills Aug. 9. (John McDonnell/THE WASHINGTON POST)

The Redskins have yet to determine their starting running back because Royster, Roy Helu Jr. and Tim Hightower have all been limited by injuries at various points this preseason.

Royster started the preseason opener, and served as third-down back in the second preseason game. He missed the third game with a mild knee injury. In his two outings, Royster has rushed for a total of 41 yards on nine carries.

Last week rookie Alfred Morris turned in the strongest performance of the preseason with 107 yards and a touchdown on 14 carries against the Indianapolis Colts. The sixth-round pick out of Florida Atlantic University has been given the night off against Tampa Bay along with the Redskins’ starters on both offense and defense.

With rookie quarterback Robert Griffin III and veteran backup Rex Grossman both resting as well, fourth-round pick Kirk Cousins will start against Tampa Bay.

In three preseason appearances, Cousins has completed 27 of 46 passes for 338 yards, three touchdowns and an interception.

Second-year pro Leonard Hankerson and third-year pro Anthony Armstrong will start at wide receiver with Pierre Garcon and Santana Moss getting the night off. Josh Morgan, who is also competing for position on the depth chart, is dressed for the game.

The Redskins’ starting offensive line will be rookie Tom Compton at left tackle, left guard Josh LeRibeus, center Erik Cook, right guard Adam Gettis and right tackle Willie Smith. With Fred Davis resting, Niles Paul gets the start at tight end. Dorson Boyce starts at fullback in place of Darrel Young.

On defense, Kedric Golston and Darrion Scott will start at defensive end, while Marlon Favorite gets the nod at nose tackle with ends Adam Carriker and Stephen Bowen and No. 1 and No. 2 nose tackles Barry Cofield and Chris Baker all sitting out.

The starting linebackers for this game: Chris Wilson and Rob Jackson on the outside positions and Lorenzo Alexander and rookie Keenan Robinson at the inside linebacker positions.

The starting cornerbacks: rookie Richard Crawford and sixth-year pro David Jones in place of DeAngelo Hall and Josh Wilson. Reed Doughty and DeJon Gomes will start at strong and free safety, respectively.