该说的已说了, 在1-yard-line run slant是很难的. 1. CB可以jam WR without

fear of being burnt, while safeties move up to crowd the area; 2.QB-WR timing has to been near perfect. The WR has to run the exact route with right count. The margin of errors is very slim; 3. When running for ball, WR is always in a vulnerable position. WR needs to turn his head to locate the ball, while CB can "face or stare into QB's eyes" for his moves.