Picture this: 90 yards of green grass right in front of you as you look on, trying to figure out what is going on down the field.
If the other team gains possession, there would only be seconds for you to come out and try to defend the attack before it develops or await the potential shot and try to defend that instead.
“Do I come out or stay back?”
One second you are having a cohesive thought or leading your defenders where to go, the next second a ball might be flying toward you while moving close to 70 miles-per-hour.