Kyle Shanahan values movement skills more than mass in his offensive linemen, which means the 49ers’ head coach initially had serious doubts about the condominium-size right tackle he inherited.

The human house is Trent Brown, who is listed at 6-foot-8 and 355 pounds, but reported for the offseason program in April well north of that weight.

“We run the ball a lot and we ask a lot of our linemen to really run numbers to numbers,” Shanahan said. “I didn’t know how it would be when you look at a big guy like” Brown.

The athletic linemen Shanahan has favored in an offense that features a steady diet of outside-zone runs are Lilliputian compared with Brown.

In his nine seasons as an offensive coordinator, Shanahan’s five primary right tackles had an average weight of 311 pounds. The past two seasons, with the Falcons, 300-pound right tackle Ryan Schraeder started all 32 games.

Despite Shanahan’s initial reservations, it’s clear Brown will be his latest right tackle. In April, when Brown reported out of shape, the 49ers did purchase insurance by signing former Seattle tackle Garry Gilliam, 26, who has 30 career starts.

However, Brown has since slimmed down and he reported for training camp under 358 pounds, the target weight the team set for him.

“I know he’s worked very hard to do that and we’re very proud of him for doing that,” Shanahan said. “The thing is, it doesn’t end right there, though. It’s every day. And it’s going to be every day forever for him. He’s a guy that can put on weight fast. But when he’s on it and he’s at his right weight, he’s tough to deal with.”

The fact that Brown reported out of shape for the second straight season is evidence that he has yet to fully incorporate elite intangibles with his All-Pro natural gifts.

Brown has gas-hose arms (36 inches) that can stonewall pass-rushers and nimble feet that belie his dimensions. His blend of size and skill has caused NFL players to gush about his potential.

Last year, Pro Bowl left tackle Joe Staley likened Brown’s ability to that of Hall of Famer Jonathan Ogden. And Denver’s Von Miller, one of the league’s best pass-rushers, termed Brown one of the NFL’s best offensive tackles after tangling with Brown in two joint practices.

Still, Brown’s spotty work ethic helps explain why he started just 11 of 23 games at Florida and was a seventh-round pick in 2015. Two years later, he still hasn’t put it all together.

In June, during an interview on PFT Live, general manager John Lynch said Brown had a great NFL future, as long as he controlled his weight and was “accountable to us and his teammates.”

“At the end of the day, it’s up to Trent,” guard Zane Beadles said Monday. “He is as gifted physically as any offensive lineman, maybe ever. But it’s coming down to that discipline stuff, again. Being able to be disciplined enough to be sure you’re taking the right steps and you’re dialed in; you understand the offense, all that kind of stuff. If he does that, I think the sky’s the limit for him.”

Brown allowed five sacks in an early training-camp practice, and had two false-start penalties Monday. Of course, such lowlights are sandwiched between countless plays in which he dominated his opponent.

Outside linebacker Elvis Dumervil, 33, who ranks seventh among active players in sacks, offered a familiar quote when asked about Brown. Dumervil noted Brown was huge and talented, but …

“Now it’s just get him in shape and really just fine-tune his technique,” Dumervil said. “… It’s just a matter of going hard every play.”

Last year, in his first full season as a starter, Brown started all 16 games and flashed his much-discussed potential. So what does he need to do to reach another level?

“I took a fresh step by coming in at a good weight,” Brown said. “I’m healthy. I’m light. I definitely feel better out there as far as the movements that are required of me, playing the position and doing the things I need to in this scheme.”

For his part, Shanahan sounds confident that Brown, despite his size, can function in his system. Brown is certainly not the poster boy for his scheme, but Shanahan isn’t ready to dismiss a player with his ability.

“I’ve never had a guy like that,” Shanahan said. “There aren’t many people on the planet like that.”

Eric Branch is a San Francisco Chronicle staff writer. Email: Twitter: @Eric_Branch

Biggest of the bunch

Kyle Shanahan had five primary right tackles in his nine seasons as an offensive coordinator and all were considerably lighter than Trent Brown, who is listed at 6-foot-8 and 355 pounds:

Ryan Schraeder (Atlanta, 2015-16): 6-7, 300

Mitchell Schwartz (Cleveland, 2014): 6-5, 320

Tyler Polumbus (Washington, 2012-13): 6-8, 308

Jammal Brown (Washington, 2010-11): 6-6, 317

Eric Winston (Houston, 2008-09): 6-7, 310

About the Author: Insidethe49

Insidethe49 Site Staff

Share This Story, Choose Your Platform!