 There is no limit to where on the field the goalkeeper can travel, although once they are outside the penalty area, they are subject to the same rules as all other players.A goalkeeper in men's football may touch the ball on the ground within his own small parallelogram, and is the only player permitted to do so.It is not permitted to physically challenge a goalkeeper while inside his own small parallelogram, but players may harass him into playing a bad pass, or block an attempted pass.The substitute goalkeeper usually wears the number 16 jersey and the third choice goalkeeper usually wears the number 31.