What about the dummy half?
The player that picks the ball from a rollball is called the dummy half.
The ball is not out (i.e. defenders cannot move forward) until the dummy has played the ball. However, the dummy half is not permitted to delay fielding the ball after a roll ball.
The dummy half may run following the rollball but if touched by an onside defender, an immediate handover occurs. Play is restarted with a roll.
The dummy half may not score.

