SANTA CLARA -- Running back Brandon Jacobs might be available for the 49ers' season opener Sept. 9 against the Green Bay Packers.And 49ers running back LaMichael James might be ready for practice later on Monday.When Jacobs sustained a left knee injury early in Saturday night's game against the Houston Texans and James went down with a left ankle injury late, there was initial concern.But the 49ers' thorough evaluations of both players alleviated those worries. Coach Jim Harbaugh said immediately after the game that both players would be fine."We were real accurate with that after the ballgame," Harbaugh said on Monday. "That assessment was accurate in both cases."Jacobs walked with the assistance of crutches Monday at the team's practice facility."I'm doing all right," he said. "I can't complain."Jacobs underwent an MRI that revealed no significant knee damage. His injury is not to the anterior cruciate ligament or the patella, Harbaugh said. Although the 49ers did not confirm the exact nature of the Jacobs' injury, a medial collateral sprain can keep a player out of action a much-shorter period of time."Brandon for the opener is possible," Harbaugh said. "Again, we'll just how to see how the treatment goes, how the body responds."Said 49ers running back Frank Gore, "Brandon's good. I'm happy that it wasn't that serious. He'll be back in a week or two. He'll be fine."James, who promised Saturday that he would not miss a practice, was Monday walking without any noticeable limp.