But neither of them are in control of the ball...

The defender is gaining an unfair advantage by blocking the attacking player's path to the ball, in order to earn his side a goal-kick/throw-in.

If he blocked an opposition players run towards the ball on any other part of the pitch in order to allow his teammate to collect the ball it would be obstruction.

There's absolutely no difference.

Posted By: Squiggles, Oct 11, 15:45:44