San Francisco 49ers

Mean but lean: What the 49ers are seeking on the offensive line

A few weeks after his freshman season ended, Nevada offensive lineman Austin Corbett stepped on a scale in the team's training room and watched as the digital number flickered between 299.9 and 300.1 before finally landing in the middle.

Three-hundred pounds. It's a magical milestone for any young offensive lineman, especially Corbett, who had joined Nevada's team only five months earlier as a 240-pound walk on.

"Within the first two weeks of being on campus, I was told that if I ever wanted to play there I had to weigh 300 pounds," he said. "That was the goal, for sure."

After hurrying to hit his mark, however, Corbett mostly stopped. Over the next four seasons, he worked on lowering his body-fat percentage and becoming as lean as possible. The heaviest weight at which he played was 305 pounds.

Twenty years ago that would have made him a shrimp among offensive tackles. These days he fits right in.

Of the 47 offensive linemen at this year's scouting combine, nine came in under 300 pounds, the most below that weight at the event in the last 10 years. That includes Texas' Connor Williams, a possible first-round selection. There also were fewer linemen at 320 pounds or above, illustrating a trend in college football and in the NFL in which quickness is prized above bulk.

"I think one thing that hurts O-linemen throughout their whole life is everyone tells them how big they have to be, which they do," the 49ers' Kyle Shanahan said last month at the combine. "But you don't want to be overweight. You want to be powerful, you want to be explosive. You want to be as light as you can, in my opinion, until you start losing strength. Because the lighter you are, the more athletic you are, the faster you can move."

Shanahan, whose offensive linemen must be fleet of foot to carry out outside zone runs, said heavy, immovable linemen can be fine in pass protection. "But it's very tough to run the ball with them, in my opinion," he said.

It makes sense then that the linemen the 49ers have examined most closely in the run-up to the draft are among the lightest in their draft class.

They have hosted Pittsburgh tackle Brian O'Neil (297 pounds at the combine) and Iowa center James Daniels (306) and had workouts with UCLA tackle Kolton Miller (309) and Corbett (305), who played tackle at Nevada but whom the 49ers see as a guard and backup center.

All of them excelled at the scouting combine drills designed to test quickness. O'Neil and Miller, for example, had two of three best times among offensive linemen in the 40-yard dash in Indianapolis. Daniels, Miller, Corbett and O'Neil also finished among the top five in the 20-yard short shuttle.

Corbett noted that different teams will want their offensive linemen at different weights. Joel Bitonio, who preceded Corbett at left tackle at Nevada, weighed 302 pounds when he was coming out of the draft, for example. The team that took him in the second round, the Cleveland Browns, now wants him at 325 pounds.

If Corbett were to be taken by the 49ers, 305 pounds might be his best weight. After all, he'd have to be quick enough to handle someone like 284-pound Rams defensive tackle Aaron Donald, whom he'd face twice a year.

"The speed of the game has changed so much in the last 20 years," said Corbett, a native of Sparks, Nev. "At the end of the day, they're not necessarily caring about a 15-pound difference. They want guys that come off the ball and are able to jump down on the defense, because defensive players are seeing that progression, too. They're light and quick off the edge and even on the inside now."

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