NASHVILLE, Tenn. (AP) — The easiest way to take the pressure off rookie quarterback Marcus Mariota will be if the Tennessee Titans can run the ball well.

Right now, the Titans are waiting for someone in a very young running back group to step up and run with the ball.

Titans coach Ken Whisenhunt says whether or not Tennessee uses a committee approach is up to the running backs.

"We can find out if we can have that guy, not to be cliché, that's the bell cow," Whisenhunt said.

"There will always be roles that are specific to certain players that do a really nice job with that. If you think that a back can stay in there for a 15-play drive, he can't do it. He just can't. It's too physically demanding on him. So you're going to have to have a third-down back."

This group also is very young. Bishop Sankey, the first running back drafted in 2014, led Tennessee in rushing as a rookie, and Antonio Andrews heads into his second NFL season looking for his first carry. Rookie David Cobb will get some snaps with the first-team offense after his preseason debut.

Dexter McCluster is the only running back with more than a year of NFL experience for a franchise rebuilding off a 2-14 season.

"We had a lot of needs we had to address in the offseason," Whisenhunt said. "I feel like we tried to address as many as we could in the right way, and we understand the running back position is a little bit young, but from what I've seen out here on the field we've got some talented guys."

Sankey started nine of the 16 games he started last season as Tennessee's second-round draft pick out of Washington. He led the Titans with 152 carries for 569 yards and scored two touchdowns.

Against Atlanta in a 31-24 loss Friday night, Sankey averaged a mere 1.9 yards on eight carries.

Whisenhunt said some missed blocks were to blame for some of Sankey's struggles and the Titans also didn't notice quickly enough that the Falcons had switched to a nickel defense. The Titans made adjustments, which Whisenhunt said helped both Cobb and Sankey.

"But Bishop had a couple of decent runs, and hopefully we'll see how that all progresses," Whisenhunt said.

Cobb, healthy after a quad injury limited him this spring, ran 11 times for 53 yards against the Falcons backups. He still looked impressive enough that Whisenhunt said the fifth-round draft pick out of Minnesota certainly deserves some snaps with the first-team offense.

The rookie set the single-season rushing record at Minnesota with 1,626 yards last season. Cobb has been busy working himself back into shape, and he has been more noticeable over the past week.

"As far as physically and quickness and speed not quite there yet where I want to be," Cobb said. "But I definitely can feel it's not nearly as sore as it used to be ... It's about gaining strength and confidence, so I can open it up and run."

Antonio Andrews, an undrafted free agent out of Western Kentucky last year, still is looking for his first handoff in a regular-season game. But he averaged 5.9 yards a carry in college where he ran for 3,674 yards, and Whisenhunt said Andrews also has a bit of a mean streak to him as well.

"So hopefully he continues to make the progress he's shown."

Copyright 2015 The Associated Press. All rights reserved. This material may not be published, broadcast, rewritten or redistributed.