ENGLEWOOD, Colo. - The 49ers have avoided another serious injury to an offensive lineman. Staring right guard Mike Person has a foot strain and is considered "day-to-day," general manager John Lynch said Saturday. On Friday, Person was on crutches and was wearing a walking boot after practice. Person, 31, started 16 games last year while gutting through foot, knee and ankle injuries. The 49ers signed Person to a three-year extension in March partly due to his ruggedness. "He's day-to-day - Person's kind of always day-to-day it seems," Lynch said, smiling. "I think that was a scare that was avoided." The 49ers have been without their starting center, Weston Richburg, throughout the offseason after he had surgeries on his knee and quadriceps. In addition, swing tackle Shon Coleman was placed on injured reserve Monday with a broken fibula and dislocated ankle. Lynch acknowledged losing Coleman was a blow because the 49ers viewed the 2016 third-round pick of the Browns as a starting-caliber tackle. However, he sounded an optimistic note on Richburg, who remains on the physically unable to perform list. The 49ers are hoping Richburg can play in the season opener at Tampa Bay on Sept....