The shifts in the Georgia Tech backfield continued Monday following the season-ending knee injury suffered by first-year freshman A-back Nate Cottrell. First-year freshman B-back Mikell Lands-Davis was moved to A-back Monday to bolster that position group.

Cottrell suffered the injury last week. Coach Paul Johnson gave the update Monday after the team’s 10th practice of the preseason.

“We won’t know the complete severity of it until they let the swelling go down, but we know it’s not good,” Johnson said Monday.

The A-back spot, as well as the B-back position, is unusually thin following the graduation of a horde of seniors at both positions. Among the seven available scholarship players at A-back, only one, Broderick Snoddy, is not a first-year or redshirt freshman. Walk-on Isiah Willis is also contending for a spot on the depth chart, although he was out Monday with an unspecified injury. Snoddy is penciled in as a starter; Tech probably needs at least two of the freshmen to develop into dependable players. Redshirt freshman Qua Searcy looks like he could be one of them; Johnson said that if the season were to start Tuesday, Snoddy and Searcy would be the starters.

“I’m concerned about every group,” coach Paul Johnson said. “But there’s enough guys in that (A-back) group to play. You’ve just got to get guys out there.”

Lands-Davis is the second player to move to A-back in recent days. Johnson shifted quarterback Matthew Jordan, who was behind starter Justin Thomas and backup Tim Byerly, to A-back Friday to give him a shot at playing time and add depth.

“We’ve got a lot of new guys, so we’re just trying to get them to be fundamentally sound, learn their assignments and play with great effort and take care of the ball,” A-backs coach Lamar Owens said.

Lands-Davis became the odd man out at B-back after Marcus Allen, Patrick Skov and first-year freshman Marcus Marshall proved themselves the top three at that position in the first nine days of the preseason. Johnson said coaches will take a look to see how the switch progresses.

Quarterbacks and B-backs coach Bryan Cook said that Marshall needs to still learn a lot of fundamentals of the position, but “he’s got really good feet. He’s got a burst.”

Johnson also said that freshman B-back Quaide Weimerskirch, whose foot injury in the spring prompted Allen to return to B-back, is expected to return following the second game of the season.