Brandon Jacobs was carried off the field following what appeared to be a significant left knee injury in Saturday night's preseason game against the Texans. Jacobs was down on the field for several minutes as Texans and 49ers players alike gathered around him in concern. The injury happened at the end of an eight-yard run and collision with Texans CB Kareem Jackson, who was also initially shaken up but appeared to emerge okay. Jacobs could bear no weight on his left leg afterwards, and was ultimately carted to the locker room. It's early, but we suspect Jacobs won't be playing football this season.