Injury behind him, 49ers’ Daniel Kilgore ready to roll

After missing the first 11 games of the 2015 season, Kilgore returned to the field just six weeks after he’d resumed running. After a 413-day layoff, his conditioning was poor and his leg wasn’t much better. Kilgore, 28, clearly has a healthy passion for the game. Kilgore’s return to health is one of several reasons the 49ers’ offensive line could be much improved this season. Last year, the 49ers allowed the second-most sacks in the NFL and sported the league’s 21st-ranked rushing attack behind a front five that struggled with right tackle Anthony Davis in a brief retirement, Pro Bowl left guard Mike Iupati in Arizona and Kilgore mostly sidelined. [...] Davis and Kilgore are on the field and they’ve been joined by reinforcements: free-agent guard Zane Beadles and rookie guard Joshua Garnett, the No. 28 overall pick who won the Outland Trophy at Stanford last year. Kilgore, a 2011 fifth-round pick who spent his first three seasons backing up Jonathan Goodwin, made a seamless transition to starter in 2014 before he was injured in Week 7. [...] he spent this past offseason at home in Blountville, Tenn. Many of his workouts were focused on regaining strength in the atrophied muscles in his left leg and were conducted at his house or high school in nearby Kingsport. Kilgore was driven this offseason by the memory of his 2015 season, which included five games and three starts. Eric Branch is a San Francisco Chronicle staff writer.