Post by Direstraits Referee on Nov 21, 2012 12:43:40 GMT 10
Under Law 5 it states that:
* An injured player may only return to the field of play after the match has restarted. * When the ball is in play, an ijured player must re-enter the field of play from the touch line. When the ball is out of play the injured player may re-enter from any of the boundary lines. * irrespective of whether the ball is in play or not, only the referee is authorised to allow an injured player to re-enter the field of play. * the referee may give permission for an injured player to return to the field of play if an AR or the fourth official verifies that the player is ready.
So in answer to the question posted that it is ok providing the ball is out of play.
Realise that we live in the real world, not an ideal one.