The relevant law is Section 10, Law 2 relating to accidental knock-on. This discussion seems to be surrounding people's interpretations of the word 'regains' within this law. If a player grounds the ball cleanly after having previously knocked-on accidentally, are they deemed to have regained the ball?
Quote Laws of the Game Section 10 - Knock on and Forward Pass="Laws of the Game Section 10 - Knock on and Forward Pass"Deliberate 1. A player shall be penalised if he deliberately knocks on or passes forward.
Accidental 2. If, after knocking-on accidentally, the player knocking-on regains or kicks the ball before it touches the ground, a goal post, cross bar or an opponent, then play shall be allowed to proceed. Otherwise play shall stop and a scrum shall be formed except after the fifth play-the-ball.
Charge-down 3. To charge-down a kick is permissible and is not a knock-on.
Heading the ball 4. It is illegal to head the ball in a forward direction.
Knock-on over Goal line
After a player, from the field of play, knocks on into his opponent’s in-goal area and he or a colleague touches down, play is restarted with a scrum where the knock-on occurred, except after a play-the-ball subject to Section 12, Law 10.'"
My interpretation in this situation is that he hasn't regained it and that in actual fact, the ball touching the ground complete's the knock-on. However there is nothing in the glossary to clarify this, the following may be of assistance though:
Quote Laws of the Game Section 10 - Knock on and Forward Pass="Laws of the Game Section 2 - Glossary"
Knock on: means to knock the ball towards the opponents’ dead ball line with hand or arm, while playing at the ball.
In Posession: means to be holding or carrying the ball.
Grounding the ball: means
(a) placing the ball on the ground with hand or hands or
(b) exerting a downward pressure on the ball with hand or arm, the ball itself being on the ground or
(c) dropping on the ball and covering it with the part of the body above the waist and below the neck, the ball itself being on the ground.'"
