CLEMSON — Halfway through spring practice, uncertainty reigns on the offensive side of affairs for the Tigers.

A young offensive staff has to decide who will quarterback, who will replace the sure hands of Aaron Kelly and how best to utilize C.J. Spiller.

But there is this to comfort Dabo Swinney and his Tigers: since 1963, when the Tigers return five starting offensive linemen, they have won 76 percent of their games.

The Tigers entered last season with little experience on the offensive line, and as a result, Clemson quarterbacks were sacked 34 times. Clemson's average yards per rush declined from 4.1 in 2007 to 3.4 last season.

Swinney is encouraged by what he has seen this spring.

"I expected them to be improving," Swinney said. "There is a lot of room for improvement. We just got some kids growing up."

Chris Hairston, Cory Lambert, Thomas Austin, Mason Cloy and Landon Walker all return, having started a combined 53 games last season. Austin and Lambert are the lone seniors.

There is some shuffling, though.

Sophomore guard Antoine McClain is with the first team thanks to his relentless play, finishing blocks with his powerful 6-5, 325-pound frame.

"McClain is probably the MVP up front right now," Swinney said. "It's a great sign to see him maturing like he is."

Austin, who Swinney says could play anywhere in the country, is moving to left guard, while Cloy is taking over first-team center duties.

The interior is the strength of the unit, helping create running lanes in Saturday's scrimmage as the Tigers backs rushed for 200 yards on 36 carries.

Clemson is also developing depth.

Cloy was unable to play due to class Saturday, and by all accounts freshman Dalton Freeman was more than adequate in his place.

While Chris Hairston figures to be entrenched at left tackle with his experience and 6-6, pass-rush deflecting wingspan, right tackle is one position in flux.

Lambert started ahead of Walker on Saturday, after Walker beat Lambert out for the starting position halfway through last season. Also in the mix is freshman J.K. Jay, whom Swinney has gushed over this spring.

The depth is having an impact on performance according to Austin: "A byproduct is more competition."

Swinney said the competition is open, and Jay — who was playing Class A football in the fall — could push for a starting spot in the summer. He says Jay losing redshirt status is not a consideration, even with Walker and Lambert as veteran options.

Swinney says the best player will play.

While there has been turnover, including a new tackles coach in Danny Pearman, the staff and players say much of the blocking schemes will remain the same.

"We'll do some zone, some gapping, some man," Pearman said. "Schemes are schemes; the biggest thing is working as one."

Pearman closed with another Football 101 lecture point: "With young receivers, young quarterbacks, it doesn't matter what you do if you can't block."

Reach Travis Sawchik at tsawchik@postandcourier.com and check out his Clemson blog at www.postandcourier.com/blogs/tiger_tracks.