According to the Boston Herald, LaMont Jordan has a calf injury, and had to sit out practice on Tuesday.
This is tough news for the Patriots. Jordan was starting to emerge as a punishing alternative to the quickness and speed of Kevin Faulk and Laurence Maroney. Hopefully, the injury will be as minor as it looked (Jordan wasn't hit hard, but fell to the ground with nothing bending awkwardly). Nonetheless, should he sit out Sunday, his absence will weaken the running game and force Matt Cassel to carry the team more with his arm.