San Francisco 49ers running back Brandon Jacobs was carted to the locker room after suffering an injury to his left knee Saturday against the Houston Texans.
X-rays were negative, according to ESPN's Adam Schefter, and Jacobs was due to have an MRI on Sunday.
Coach Jim Harbaugh told reporters that Jacobs would miss time but that the injury was "not the you don't come back from variety."
Jacobs was injured on an 8-yard run in the first quarter when cornerback Kareem Jackson hit Jacobs' knee. Jacobs stayed down for several minutes before being helped off the field and later taken to the locker room on a cart.
Jacobs, who spent the first seven seasons of his career with the New York Giants, signed a one-year deal with the 49ers after the Giants cut him in March. He was slated to back up Frank Gore.