With San Francisco 49ers wide receiver Mario Manningham inactive for Thursday's game against the Seattle Seahawks, running back Brandon Jacobs cracked the game-day roster for the first time as a 49er. Manningham was limited in practice the previous two days because of a shoulder injury. In six games this season, he has 24 receptions for 258 yards and one touchdown. Jacobs was Manningham's teammate last season with the Super Bowl champions New York Giants before both joined the 49ers. Jacobs sat out this season's first six games due to a left knee injury, though he said earlier this month that he was healthy and ready to return to action. Last week, before the 49ers played host to the Giants, Jacobs publicly disputed San Francisco coach Jim Harbaugh's assertion that Jacobs was still unfit for action. That led to a meeting between the two, but it didn't get Jacobs on the field against his former team. Jacobs didn't have a carry in the first half against the Seahawks.