Running back Robert Kelley (No. 22). (Brynn Anderson/Associated Press)

The third preseason game is considered a dress rehearsal, yet the Washington Redskins will likely face the Buffalo Bills on Friday without their top two running backs. That will pave the way for undrafted rookie Robert Kelley to make another lasting impression.

Kelley will get a heavier workload as he’ll split carries with seventh round pick Keith Marshall. The Redskins have already ruled out Matt Jones, and Redskins Coach Jay Gruden said Chris Thompson would probably sit out against Buffalo. As a result, the Tulane product has worked his way up from the bottom of the depth chart to receiving first team reps this week in practice.

“Sometimes when you’re moving up as fast as I’m moving up, you kind of get ahead of yourself,” Kelley said. “I’m trying to make sure that I stay grounded, do the things that I know and play by my principles.”

The 23-year-old isn’t trying to steal Jones’s starting job. He knows how the pecking order will be once Jones and Thompson return. Kelley said he’s focused on staying true to his game and avoiding missed assignments in an expanded role with the hopes of becoming the team’s third running back on the 53-man roster.

“Just being humble and respecting the people around me – my teammates,” Kelley said. “Obviously Matt is out right now, but we know he’s going to get back. I don’t want to be the guy that tries to act like I’m trying to take over. I want to play my role.

“I’m always going to be confident in myself and the way I play the game but what I mean about getting ahead of myself is start getting cocky, start to try and make plays I know I don’t make. Focus on carrying the ball right because when you get [cocky] out there, you start getting loose with it and feel like you can do more than you really can do. … You’re trying to turn into Superman out there, and that’s what I don’t want to do. Everybody like to be Superman, but you’ve also got to play the game you know how to play.”

Kelley made a strong impression in the preseason opener against the Atlanta Falcons, rushing for 40 yards and a touchdown. He received fewer carries against the New York Jets last week, gaining eight yards on three attempts, but Kelley began to receive reps over Marshall on the second team following the Falcons game. Listed at six feet and 228 pounds, Kelley will get more touches given his usage with the starters this week. Kelley will attempt to show that he’s a backup capable of stepping in to serve as a threat in the run game with quarterback Kirk Cousins under center.

“I think you just try not to mess up when you’re with the vets,” Kelley said. “You don’t want them to go out there and like, ‘Oh, we can’t depend on this guy.’ So you don’t want to take it for granted. You want to go out there and get the work in, but you also feel good about yourself going with the ones.”