No number.

SO the rules of a competition say that all players must have a number on their Jersey.

A player is injured and is removed from the field. The injury involves blood and the player changes his Jersey, but the new Jersey does not have a number.

The referee sees the player on the sidelines in the new jersey (without seeing the back to realize there is no number) and waves him on to the field but the AR notices the Jersey does not have a number and trys to get him to stop but the player is already on the field and continues to get involved in play.

During the course of play the team that has the player without the number scores a goal.

What would you do.

(BTW this happened in the Champions league game last night between Columbus and Santos in Mexico, so you can guess which team got screwed IMO)

Was the goal scored by the player without a numbered top?

No, but he played the ball before the goal, although I'm not sure what difference that makes.