New York Giants' linebacker Mathias Kiwanuka broke his left leg Sunday against the Detroit Lions, and running back Brandon Jacobs left the game with a hamstring injury. X-rays revealed Kiwanuka broke his fibula. Late in the third quarter Jacobs limped off the field while trying to keep weight off his left leg. He did not return. Kiwanuka was hurt when teammate Osi Umenyiora rolled into him while making a tackle on the second play of the game. He was helped off the field, keeping his left foot off the ground and was later taken toward the locker room on a cart.