Brady was hurt in the first quarter while attempting to launch a deep pass to wide receiver Randy Moss. While Brady was able to get the ball off, Chiefs safety Bernard Pollard rolled into his leg. Pollard was already on the ground courtesy of a Sammy Morris block. Morris buried Pollard who was coming on a blitz, but the Chiefs defender crawled toward Brady as teh play went on, then launched at Brady's legs to disrupt the pass.
After Brady threw, Pollard rolled onto Brady's left leg, pushing the knee at an awkward angle. Brady went down in a heap. The training staff rushed immediately on to the field to attend to Brady who was rolling on his back clutching his knee.
Brady left the game and did not return. In his place, backup quarterback Matt Cassel guided the Patriots the rest of the way. Brady was initially announced as being questionable for a return to the lineup. After the half, the team announced he would not return.
New England has benefited from having Brady under center the past seven seasons. He has started 127 consecutive games heading into Sunday's game against the Chiefs, third only behind Brett Favre (275) and Peyton Manning (173).
Brady will undergo further testing after the game. The team has not made an announcement on the extent of his injury.
The Patriots won 17-10 on a defensive stand inside their own 10 yard line. They improved to 1-0 with Cassel at the helm, and may have to rely on the former USC backup to Carson Palmer and Matt Leinart for some time to come.