Coach Dick Jauron said it's not clear how much time the first-round draft pick will miss, adding he first wanted to consult with McCargo and the team's training staff.

Jauron spoke before the team announced the extent of McCargo's injury on its website.

McCargo was hurt in the fourth quarter of Buffalo's 40-7 loss at Chicago on Sunday. It's not clear on which play he was hurt, but McCargo was spotted on crutches while leaving the locker-room.

It's the same foot McCargo broke as a junior at North Carolina State last season, an injury that forced him to miss five games.

Selected 26th overall, McCargo was the second of Buffalo's two first-round draft picks. He has appeared in all five games this season and has eight tackles.

Buffalo (2-3) will have to determine whether to add a player this week to fill in for McCargo because the team is down to three defensive tackles ahead of Sunday's game at Detroit.

McCargo's injury further depletes a defence that's already without two key starters: veteran linebacker Takeo Spikes, who's missed four games with a hamstring injury, and veteran safety Troy Vincent (hamstring), who was placed on injured reserve during Week 2.

Spikes is improving and could be ready to return this weekend.

``I feel better now than I did last week and, for me, mentally and physically it's a great start,'' Spikes said.

Starting cornerback Nate Clements' status is also uncertain after he hurt his right leg and left wrist against Chicago. Jauron said Clements is sore and the team won't know until Thursday whether he'll be able to play this weekend.