
The Houston Texans are in the midst of a four game losing streak that has their season in jeopardy, and they may have just lost one of their best defensive players:
Brian Cushing is writhing on the field after taking a blow to his left knee. Does not look good.
— Jason La Canfora (@JasonLaCanfora) October 20, 2013
Jamal Charles went low to take out Brian Cushing. Texans LB getting carted off….
— Andrew Siciliano (@AndrewSiciliano) October 20, 2013
Brian Cushing is being carted off. Texans have lost Cushing and Foster. Tate has been out but should return. Trail 17-13.
— John McClain (@McClain_on_NFL) October 20, 2013

The play happened after Kansas City Chiefs running back Jamaal Charles was in pass-protection and blocked low on Cushing as he was blitzing on a play, and immediately hit the ground screaming in pain.
If you recall, Cushing is already in the midst of a comeback season after suffering a season-ending ACL tear last year when he was low-blocked by a New York Jets player in a Monday Night Football game.