Dave Rayner's bad squib kick hit Cook, who was an up man on the kickoff return team. Cook quickly identified what happened and hustled to the ball, falling on it for a New York recovery. It gave the Jets a short field and set them up for the tying score before the half.
That game might have been very different without that play. The Bills had the Jets on their heels at that point after converting a bad Mark Sanchez interception into points. Buffalo might have attacked had it recovered that kick and gotten a back breaking score before the half.
Sometimes making a play can be as simple as just showing hustle. Cook getting to that ball yesterday was one of the most important in the game.