49ers’ Trent Brown needs to watch his weight

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. 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. 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. [...] Brown has since slimmed down and he reported for training camp under 358 pounds, the target weight the team set for him. 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. [...] Denver's Von Miller, one of...