The pallino must pass across the center line without hitting the back wall in order for it to be a valid throw. If the pallino does not pass over and clear the center line the other team will roll the pallino, and so on until the the pallino throw is valid. The team that first attempted to place the pallino will play the first ball.
A ball is valid as soon as it passes over the foul line, or lag line. A ball does not have to pass over the center line to be considered valid and in play. Balls cannot hit the back wall without first striking another ball or pallino.
Note: When a player wishes to approach the center to meet with a team mate or to view the situation closer, it is very important that they do not carry a ball in their hand over the foul line. When the ball passes over the foul line it becomes in play and if the player is holding the ball, the ball is nullified.
The illustration above shows that the pallino has not completely crossed over the center line.