If a defender kicks the ball back to their fullback, who then misses the ball leading to the goalkeeper picking it up, what is the restart?

In this scenario, the restart is an indirect free kick. According to the Laws of the Game, a goalkeeper is not allowed to directly handle the ball if it has been deliberately kicked to them by a teammate. This results in an infringement of the rules when the ball is picked up by the goalkeeper after being unintentionally missed by the fullback. The indirect free kick is awarded to the opposing team from the location where the goalkeeper handled the ball.

The nature of the infringement hinges on the connection between the defender's actions and the goalkeeper's handling; since the ball was kicked by a player on the same team, the rules dictate that it cannot lead to a direct free kick or a penalty kick in this context. A throw-in also does not apply here because the ball was not out of play. The proper course of action is to restart the game with an indirect free kick for the opposing team.