As Emmitt Smith said on Sunday, the Giants provided the “bootprint” for playing the Patriots:  Hit Tom Brady, early and often and with significant force.

The Chiefs did just that early in Sunday’s regular-season opener, and sent shock waves throughout the league.

Brady was hit low by safety Bernard Pollard, buckling Brady’s knee — as this photo of the hit from ESPN.com illustrates.

Every so often, there’s a significant injury in Week One that changes the landscape of the season dramatically.  In 1997, it was a torn ACL for Jerry Rice, courtesy of Warren Sapp.  In 1999, it was a busted Achilles for Vinny Testaverde, courtesy of the green cement that used to cover the field at Giants Stadium.  Remember Keyshawn Johnson’s post-game podium-pounding tantrum?

(There might be others.  PFT Planet, feel free to refresh our memories.)

If Brady is out for the year, it would be the biggest opening-day season-ender in league history. And it significantly would open up the competition in the AFC.